You'll want to be careful where you'll place your characters. The characters in the front row get the full effect of the attack, so you'll want to place them depending on their strengths and weaknesses. As always, the leader will receive the brunt of the attacks in every fight, so it's important to have a strong, well-armored character as the leader. In the back row, characters take less damage than the characters in the front row, but they also cause less damage to enemies than the front row characters as well.
As in every adventure game, you must talk to everyone and I mean, everyone repeatedly in order to succeed in your quest. If someone doesn't want to talk to you at the moment, wait until something major happens and that person will tell you anything you want to know. So, after some major event happens, talk to people the second time around and they'll have something different to day.
When fighting a group of monsters, you'll want to spread out your attack. If there's more than one type of enemy in an enemy party, it's best to attack the enemies that pose the biggest threat first. If you don't, that monster(s) will stay alive longer and cause more damage to your party.
You should also use that monster's weakness to your advantage. For example, enemies made of Fire are weak against Ice attacks, Ice and Water creatures' weaknesses are Fire and Lightning and creatures of the Undead are weak to Restoring and Curative attacks.
If you're constantly getting whupped by certain enemies, you probably need to raise your levels. If you don't, the stronger enemies in the game will work you over like the true weaklings that you are. You should best gain experience near a town. That way, you can walk in and take a rest when you're getting your butt kicked.
When you know you're not going to win, it's best to run away from a battle. This may become harder to do in dungeons since you have limited space to run. BE CAREFUL THOUGH, if you do run away successfully, there's a chance you might drop some of your money while you're running away. Note: You can't run away from bosses, so don't even try.
Once you've raised your characters to the desired levels, be sure to purchase the most powerful weapons, armor and items available. When purchasing stuff for the party, purchase for the party you're currently playing with. Only purchase for the remaining characters when you have an overabundance of gold. Also, throw away any stuff you feel will become useless. For instance, a Cure-1 potion will become obsolete when you get into higher levels. Be sure to equip the new weapons and armor you buy for your party 'cause that fancy sword or shiny armor will amount to no good if you're just carrying it.
Before throwing away any items, make sure if you can use that as an item first. For instance, a Cure wand will recover lost HP for the party when it's used as an item. Items you can't throw away or sell are considered important items that will be handy at some point in the game.
In the game, there are two types of magic; black magic and white magic. You can choose whether to affect one person or all the people in the group. Keep in mind that magic spells casted on a group of characters is less potent than a magic spell casted on only one person. You must use this to your advantage if you want to win in battle.
Throughout the game, you'll sometimes get attacked from behind. When this happens, your character's positioning is reversed, meaning that back row characters are in the front and front row characters are in the back. In order to minimize damage in this sutuation, you'll want to change the character's positioning by using the Change command. Using this will place the characters back in the right rows.
You can also use the Parry command to put your characters in a defensive position. When they are in a defensive position, they'll receive less damage until the next turn. Use this when you're running low on HP and you're facing a powerful enemy.
Along the way, you'll have access to certain vehicles which will prove to be a factor along your quest. The Hovercraft you find can travel anywhere except the oceans and rough terrain, though you can cross shallows, which are rocks in the water, with it to get to otherwise unreachable places. The Airships can go anywhere in the world, but you can only land in grassy plains. There are also Chocobos you can ride on as well. To find them, go to a round shaped forest. There are two kinds of chocobos you can ride on. The Yellow Chocobo can go just about anywhere except the ocean and the mountains. The Black Chocobos can go anywhere except mountains. As far as landing goes, you can land a yellow chocobo on grassy plains while you can land a black one in the forests.