any dms (myself included) often gloss over monsters, using them as fodder for the PCs thirst for power, treasure, and fame.  Dms include monsters without thought as to why that monster was used other than it has so many hit dice, XP, or so much treasure.  Dms tone down the monsters so that the PCs can encounter the monsters at lower levels. (why if the monster serves no purpose story wise, why tone it down, and why cause the encounter in the first place. )   This is a waste of a perfectly good monster, unless like in my case with undead (where I feel that some of the monsters powers are poorly based on myth, like the vampire.)  The worst offenders of dm misuse are truly high powered monsters (dragons, hydras, demons, and Undead) and the lowly humanoid (goblins, Orcs, kobolds, hobgoblins, ogres, giants, etc.)
	Continuing with my rant, I absolutely despise the use of Kender, and gully dwarves.  The reason why is again full 95% of all gully dwarves while tool users, (which makes them immediately smarter than chimpanzees) don’t have the functioning intelligence god gave a grapefruit.  This lack of intelligent self-preservation would result in the genocide of the race.  Gully dwarves have 1 basic food source besides the odd and end vegetable material and that is rats. While they have numerous predators, and are treated as vermin similar to rats.  Gully dwarves have neither the reproductive rates of rats or goblins and they would be extinct in a balanced world in 6-7 generations. (So please if you use gully dwarves please play them with a functional intelligence that is more inclined to the survival of the races.)   And Kender, this race is almost perfect, however if played out within the guidelines within of the dragonlance novels, this race wouldn’t last nearly as long as a gully dwarves meal.   Kender are easily distracted from routine day to day operations.  So I can imagine that child rearing would be almost an impossible task.  I mean the baby bottle would be continuously missing as neighbors would acquire it. (The baby could even be acquired.)  This flighty race seem to have only one natural instinct and that is to be struck with wanderlust.  Wanderlust would definitely raise infant mortality by roughly 1,000 fold.  Plus with their inborn curiosity, they would seem to make excellent students, but their lack of focus, inability to pay attention, and the ease at which they are distracted would detract from any serious studies the whimsical Kender could conduct.  The race would have to adapt, because with no fight or flight instinct (fear), and self-preservation the race would have limited to the advancement level of animal food, being wiped out by larger more focused predators (lions, tigers, bears...oh my.)  For those readers and dms who maintain  that it is just a game, They are entirely correct, however a game that is not at marginally realistic will lose edge, feel, and desirability of play.   Imagine playing monopoly and changing dice rolls to drawing random numbers from a hat, while the same game is still played the latter method drains away some of the fun.  I mean if a world creator can not put more thought into his efforts, a player might as well play Final Fantasy I-IX, or Diablo I-II.  Now that I have gotten it out of my system on with the show.
Monster Ecology:  Monster placement is crucial to a realistic feel to any rpg.  In Dungeon and Dragons monster placement is helped by climate/terrain and frequency heading of the creature.   In placing monsters take in to account the amount of food, and water needed for the creature.  There is no hard or fast rule regarding how much food a particular monster can and can’t eat.  When placing monsters the predator to prey ratio should be tipped in favor of the prey.  No natural monster including humanoids would completely wipe out prey in any given area.  However if a predator race becomes to numerous (as in the case of humanoids) over predadation does happen. Also if a predator is over hunted and its numbers fall, if the prey become to numerous endangering the welfare of the plant and insect life.  The more intelligent the monster or animal is the aware of their effect on the natural order.  See the sample food chain below
				Dragon
		Griffon		Orc		Man
				Omnivores(bears) / Carnivores (lions)		
				Insectivores(Lizards) / Herbivores (deer)
				Insects/Plants
				Plants
Monster Placement:  Now that the standard ground work of monster ecology is basically understood, it is time to place the monsters.  Placement of animals in a geographic location is not real difficult, and is rarely abused.  The abuse stems in monster placement in dungeons, ruins, crypts, and caves.  Most ancient human civilizations (including the cavemen) were superstitious and avoided places of death, and yet humanoids flourish because a dm wishes them to occupy his dungeon. Humanoids are just as advanced as any cavemen and their society would be racked with superstitions, spirit worship, and fear of the unknown.   These humanoids would select areas that would offer protection, food, water, and safety from harmful spirits.  This simplistic belief can be subverted by desperation, or events beyond their control.  
	All creatures must have access to and from a food source and watersupply.  Any humanoid creature must have a relative degree of safety (or expectation of safety) in its lair.  Placing monsters wily nilly in a dungeon is waste of a perfectly good plotline, dungeon, and or story.  Now this doesn’t mean that humanoids and monsters can’t be found in dungeons, it just means their must be a reason for them to be there.  The reason can be fairly simple.  They moved into the dungeon for protection of the elements, abundance of natural resources, or flight from surface persecution.  Non-humanoid monsters inhabit dungeons for much the same reason.  However, if no food and water source is avialable, the monster will not stay long.  So in short, all monsters (natural and unnatural have to placed for a reason, besides the dms wishes.) IF YOU  DON’T HAVE A REASON FOR MONSTER PLACEMENT, THEN DON’T USE THE MONSTER.
	This method will lengthen the time it takes to populate a dungeon and flesh out adventures, it will add flavor and realism that will amaze the players.
Humanoid Myths:  Humanoids are portrayed as stupid, savage, and dirty.  This is a stereotype not how the humanoid should be played.   Native Americans suffered from the same prejudice and stereotypes from the Europeans, that the Humanoids suffer from Players, Human, Demi-Humans, and Dms.  These stereotypes while adding to the flavor and realism of the game should never ever be held by a DM.  If a dm is prejudiced against any monster (including humanoids) then two things must be done.  The dm needs to work on rectifying his prejudice (not that hard, usually) or the easiest way never use the monster until he or she has shelved the prejudice.  Humanoids (goblin, gnolls, Orc, hobgoblins, kobolds, goblins, ogres, hill giants to name a few.) are never played intelligent or even portrayed intelligently in books.  This is a shame.  A good humanoid can make a poor story a little better, and a good story excellent.  The Easy approach on dispelling the stereotypes for dms is as follows.  No predatory animal has a horrific body odor. The odor would interfere with hunting. (true animals do roll in carcasses, and bathe in mud...but these serve a purpose..to mark food as theirs and to prevent insect irritation.) All animals use some form of hygiene (apes groom each other, cats lick their fur, dogs bathe and lick their fur)  While this doesn’t make them clean, it does keep them free of parasites to some degree. Animals will not eat, or rest in their own waste.  (exceptions occur if the animal caged or tied up.)  Animals will not overhunt an area (again unless the balance of nature is disrupted this will never happen.)....so why would the humanoids do something that even animals do or do not do.  Now humanoids don’t usually overhunt an area, however if left alone the population explosion would have horrible effects on the ecology, resulting in over-predation.  Humanoids would not live near their own waste (unless it was completely unavoidable)  Humanoids would try to remain pest free (not because of health concerns, but because the nasty buggers itch and hurt)  Humanoids would be not as filthy (to mask scents while hunting)  Humanoids would not live in a hostile environment. Humanoids would not attack anything that moves, or always flee if overmatched. Humanoids are much more complex depending on the type of society, the type of humanoid, and the history of the society.
Average Humanoid Intelligence: 1 (animal) 2-4 (semi-intelligent/retarded human)5-7 (low intelligence)8-10 (average (human) intelligence) 11-12 very intelligent, 13-14 Highly intelligent, 15-16 Exceptionally intelligent, 17-18 Genius
Bugbears: (int: 5-10) Flinds (int: 8-10) Goblins: (int: 5-10) Gnolls: (int: 5-7) 
Hill Giants: (Int: 5-7) Hobgoblins: (int: 8-10) Human (int: 9) Kobolds: (int: 8-10) Minotaur (int: 5-7) Mongrelmen: (int: 5-10) Orc: (int: 8-9) Ogres: (int: 8) 
Ogre Mage (int: 9-16) Urd (int: 5-7)
	This means that gnolls, minotaurs, urds, and Hill giants have lower than human intelligence (sages believe is because they descend from non-primate animals, while goblins, Mongrelmen, bugbears have low to average intelligence, while Orcs, hobgoblins, flinds, and  Ogremages are at least as smart as a human.  So in games terms.....stop playing the Humanoids like the retarded cousin that no one wants around.
Bugbears:  A burly giant race of goblin.  They are clumsy looking and walk with a shambling gait.  However these brutes can move quite swiftly and with great stealth.  Bugbears (unlike their smaller cousins) have excellent vision (no penalties in light or darkness) and keen hearing.  They are excellent hunters, and are cannibalistic by nature.  Bugbears have the reasoning capacity of a drunk man.  They have little patience for true manufacturing techniques (using crude weapons, and animal hide clothing unless booty from raids.) Instead they rely upon brute force, and intimidation to get all that is required.  Bugbears have no concept of theft, murder, or any other crime besides breaking of Taboo.  The whole society is based on might makes right (much to the detriment of the weaker females.)  The society however does fear, and respect the female Shamans.  The Shaman is the spiritual leader, and judge of the bugbears. The Shaman declares what is Taboo.  Anyone caught breaking Taboo are hamstrung and left to die or buried alive. 
	This race is beginning to show signs of dying off.  The extinction is created by several factors:  Ale and wine (which they often drink to excess),  Hunting area becoming dominated by smaller humanoids (goblin) and the encroachment of man.  However Bugbears have been taking small family groups and living within a goblin clan hold for mutual gain.  Bugbears barely control their  primitive side, which separates them from beast.  Bugbears collect the bones and skulls of slain victims, often residing within the grisly remains.  
Gnoll/Flind:  Huge brutish animal men.  The Gnoll is both larger and less intelligent then its smaller cousin the Flind.  Gnolls are hyenamen and Flinds are bearmen.  These humanoids roam the land in nomadic loose bands.  The only real organization is had when the Flinds have control of a tribe.  Gnolls (who resemble hyenas) have a faint musky smell to them (similar to the hyena) and they often travel with packs of the beasts.  Lead by the Largest most powerful female (unless flinds are around)  They use simple tools (stone weapons) and animal hide clothing.  They will also used scavenged metal from raids.  (the monster manual says that gnolls leave beneath the ground or in ruins and this is  false, they only go underground during birthing and child-rearing times(winter).)  All raids and war parties are lead by the most able female.  All Gnoll females are larger and more powerful then their male counterpart.  Gnolls rarely fight amongst themselves and then rarely to the death.  Gnolls worship Spirits of the Dead, and the Great Mother.  Gnolls communicate with their own language and scent markers.  Pups are raised collectively by the females and kept separate from the males (who would eat the pups).  
	Gnoll males are used for war and raids, while the females manufacture everything the tribe needs.  Gnoll males are possessions controlled by the females.  Gnolls circle through their territory and use repeated birthing dens (underground lair) for the pups.  Favorite gnolls tactics is indirect confrontation, superior numbers, and misdirection.  The Gnoll rarely makes permanent structures. (the only known cases are when lead by flinds)  Gnolls will never unite with other races or follow any non-Gnoll unless being led by flinds.  The gnolls believe that flinds are the children of the Great mother and will obey fanatically.   Gnoll shamans, witchdoctors, and clerics are always female because of the will of the Great mother.
Goblins:  These small humanoids are the later descendants of bugbears.  They are cunning, vicious, completely foreign to what humans can understand.  Goblins are very structured in their way of life. Females gather food, prepare meals, raise children, and act as shamans. Male goblins are hunters, workers, warriors.  A male goblin has a career dictated by the chief (hunter, mine worker, metal worker, wood worker, warrior, slaver) The goblins use the females as possessions and a measure of success.  Females are forbidden to use weapons, and any female who violate this law has her hands amputated by the clan punisher and then left in the wilderness to die.  Males who shirk their duty are Staked on the clans perimeter to die from their wounds or exposure.  A chief is always the most successful non-warrior class.  The Chief is served by his warriors who preserve the goblin way of life.  The goblins are quite organized.  Weakness and illness is cared for by family members and females.  Goblins crudely mine ore, and have a developed slave trade, and have a meager trade (raw ore for finished goods.)  
	Goblins warriors are the offensive arm, while any male will take up arms to defend the clan.  Goblins worships gods, and spirits of their ancestors.  Goblin history is remembered and retold by the clans shamans, and priests.   Goblins are an underdark race, and only venture outside during the night because of their sensitivity to light.    While goblin are not as savage or barbaric as people believe they will eat almost anything except each other.  Goblins will also eat carrion like most predators.  Goblins also have a sadistic streak.  Goblins have no moral center (like humans) so death, killing, etc. rarely exhibit the proper emotions.  All goblin rites (religious and otherwise) are always punctuated by live sacrifices (slaves and goblins alike)   Goblin caves are always have the following things in common.  They have a common room for each profession, brood room for the young, private quarters for nobles and chief, a waste pit, food storage, and slave area.  Goblin caves have an odor to themselves however they are not vile dens of evil (unless you enter the slave area, and waste pit) but they are tainted like living next to a stockyard in a human town.  
Hobgoblin:  This dour, grim warlike race is similar to Klingons from Star Trek (if a dm grapples with the equivalent)  They are advanced miners, and workers of metals.  They rarely work with fine cloths preferring function over form.  Hobgoblin Artistry is based on warfare.  The ultimate Hobgoblin artist is a weaponsmith. Hobgoblins are similar to dwarves in this respect.  These proud, honorable people can be found above and below ground in permanent structures.  Rarely if driven from their home they will inhabit structures created by lesser (any non-hobgoblin) races.  Hobgoblins whole lifestyle revolves around war and the committing of the war.  Hobgoblins value weapons, strength, honor, and courage.  They are a force to be reckoned with, however, their xenophobic nature to foreign hobgoblins prevents them from uniting and displaying their true prowess.
	Hobgoblins are a civilized, but brutal race.  A hobgoblin would never wield poor quality arms or armor.  A hobgoblins weapons and arms are tied directly to his entire belief system including honor.  Hobgoblins are similar in outward appearances to feudal Japan.  However hobgoblins are also realist.  Retreat is not unhonorable as long as the withdrawal will serve an even greater purpose.  Clan and clan leaders welfare are taken before the individual welfare of a hobgoblin.  Hobgoblins have an intricate society that has  a near religious devotion to war.  Shamans serve as the ancestral advisor, while clerics serve to prepare the faithful for death in battle (True death.)  Weakness in body and mind is never tolerated.  A weak or chronically unhealthy  hobgoblin is killed by the shaman to protect the clan.  Hobgoblins violating the laws of the clan are punished according to the chief, from handicapped battle, to maiming, to banishment, to finally the worst punishment sold to slavery.  
Kobold:  Small humanoids who intellect and society is based on survival.  They fashion crude weapons and scavenge for other items that they need.  As a society based on survival they follow the greatest survivor.  Kobolds survive by being masters of trickery, ambush, and overwhelming odds.  Kobolds wish to conquer the world, however due to their lack of physical strength and size they have reverted to trickery.  Kobolds  are sadistic, yet basically a cowardly lot. Kobold lairs are well trapped and kept free of debris.  Kobolds are sporadic hunters who rely heavily upon their traps and ambushes.  Kobolds while unable to grasp many abstract thoughts (such as good, evil, kindness, peace) they have an almost innate ability to manufacture traps.  Kobolds also have a tendency to coat weapons and traps with their waste. They realize that waste can make others sick.  This realization does not stem from medical or hygenic astuteness, but because of the mortality of any slaves taken by kobolds.   Kobolds will always use hit and run tactics unless an opportunity arises for overwhelming. The overwhelming tactic is only used when they outnumber 15 to 1 the creature being overwhelmed, or the target is confined in a limited space..  Of the humanoid races, the Kobold is vilest, most sadistic, and inhumane of the lot.  Kobolds are always frustrated and Kobold society is often dotted with murder, mayhem, and larceny.  Kobolds make poor slaves, or pawns because they hate authority including their chief’s.  This  bad attitude and the physical weakness is what has limited Kobold advancement as a world power.  Kobolds are often employed as assassins, and saboteurs.  They would be an natural unbalancer to any ecological system wishing all life dead (except that almost everything is more powerful than them.)  Kobolds are the humanoid equivalent of the velociraptor.  Kobolds do not keep very good records of their history, however any records are kept by the priestly classes.  Clerics, shamans, witch doctors, and any other spell caster are considered demons and are feared by kobolds.  Kobolds devote their life to destruction, causing pain, and death. Many races laugh and criticize kobolds, however most encounters of kobolds are enslaved, where the beasties are not prepared or willing to defend the area being invaded.  The true might of kobolds have yet to be displayed.    
Mongrelmen:  Poor and unfortunate race of beings, who are born in squalor.  Mongrelmen when freed are clean, calm, peaceful pacifist who love art, literature, music, and try to scratch out a living, well away from any outside influence.  Enslaved Mongrelmen are the stereotypical humanoid, dumb, dirt snuffling beastman, who live in their own waste.  Mongrelmen when shown kindness, are loyal friends and noble people, however most are degraded to inhuman standards.  Mongrelmen have served as assassins, thieves by many darkoverlord.  Mongrelmen while peaceful are pragmatic. Any Mongrelmen enclave is well protected. They have become Xenophobic, killing any non-people who enter their territory, Failure to do so could result in enslavement again.  Any mongrelman who shirks his duty to protect the enclave is immediately slain, his body is then buried.  Mongrelmen believe that unless a body is burned the soul is forever doomed to this earth.  Mongrelmen are a tragic race whose horrific features do not reflect the beauty within their soul. Mongrelmen have no known written language however all have the understanding and ability to learn to write in other languages.   Mongrelmen when confronted by outsiders play to be stupider than they actually are. Mongrelmen actual intelligence is the same as a humans.
Ogre/Ogre Mage:  Huge brutish, behemoths.  These massive humanoids have a limited intelligence, but again they are smarter than animals.  They use animal hide clothing, and weapons are not manufactured but traded for, unless using clubs.  They have attempted to manufacture weapons however their strength can break any crudely made weapon (unless a club)  Ogres while savage, have an amazing cunning.  Their limited intellect is devoted to food, mating, and sleeping.  Ogres will eat any meat, and vegetable material (including sentient races.) Ogres follow Vaprak (a great ogre hero and god)  Ogre shamans are rare, however not unheard of .  Ogres have a simple society based on family ties.  Ogres often are believed to be  wandering stomachs, who bash and crash, while mainly true Ogres have great family ties, and are usually non-aggressive versus other ogre families.  Ogres have also been known to adopt other races and raise as their own.  Ogres have a distinct body odor which they pride themselves on.  The odor is used in their hunting techniques.  Ogres pride themselves on their strength and ability in unarmed combat.  Ogres despite their size and body odor are very capable ambushers. 
Orcs:  Aggressive and Tribal the Orc is the most common humanoid to be encountered.  The Orc is also the most documented humanoid race.  Orcs society is dominated by males, with females being property, who only function is to be bred, serve males, and tribal upkeep (plant gathering, cooking, washing, etc.)  Orcs are similar to Native Americans along some of their beliefs however they are descended from darker stock.  Orcs evil nature is manifest inside their lair and raiding habits.  All men on raids are enslaved or killed, while all women are enslaved as breeding stock.  Orcs will mate with just about anything.  Orcs advancement as a society is limited by the warfare from all sides, (elves, goblins, hobgoblins, other Orc tribes, dwarves, humans, ogres, etc.)  Orcs will not eat a sentient race, but will eat any other type of meat (except carrion).  Orcs will also eat the internal organs of enemies and other Orcs due to beliefs of physical powers are located within these organs.  Orcs do not like or tolerate magic (except for their shamans, and clerics)  Orcs live a harsh life, where death is mere inches away, at any given moment.  This awareness and closeness to death has made them harsh, and brutal.  This race while primitive has the ability to accomplish great feats.  These Orcs are not nomadic and their dwelling resemble a human settlement from a distance.  They have their own written language, forms of art, history, literature, etc.  Generally however Orcs are action oriented with crafts work being more predominate than any art.  Orc cities while underground are similar in many ways to elven cities.  Orcs are governed by laws set forth by the tribal chief, or in the case of city dwelling the Overmaster and his court of chiefs.  Orcs birth rate, intelligence, and proclivity to violence make them a huge threat to the other races, however the Orcs ability to not unite, and inability to restrain from warfare limit their chances for success.