1:ONLY PHB RACES AND CLASSES! With two exeptions. First, with the DM's approval, you can have any Prestige Class. Second, Orcs are a playable race as well. Orcs take a different ethos in Amristar than standard Orcs in D&D, are more balanced, and are by definition, demi-human. Anyone who seriously needs a non-demi-human race to be played in their campaign needs to submit an E-mail to me with a written explanation and a rough-draft character sheet (DMs only).
2:Keep in mind the limited magic in Amristar. Amristar is in many places considered to be a low-magic campaign. Magic is expensive, rare, and most characters should not see an enchanted weapon until level 5-10. Storywise, it serves the purpose of making magic something truely mystical and treasured. Game-wise, it's to put a clamp on overpowering characters, and to encourage them to make do with the same crap every other mortal has. A simple longsword is way out of the price range of a commoner. A +1 Longsword, over a thousand times more expensive, is worth more than most towns' assets.
3:You'll want to read about your race's and class' place in Amristar and integrate it into your character's life.
4:It is highly encouraged that all characters start at level 1, and at around level 15, standard battles begin to dissapate. As an experienced DM, I know that most encounters for characters in high levels are so complex that simply picking up a new monster and throwing it at them, even if the challenge rating is overpowering, it is still no contest because the players know their characters like the backs of their hands, and have had quite some time to tweak their abilities and work as a team. Suggested alternatives are heavy RP sessions, and increased opportunity for enviromental death. Keep in mind, level 15 characters have the ability to Wish, go to any plane, and pretty much conqer the world. At level 20, your character should be retired or preparing to enter the realm of demi-godhood.