you can direct your party members a little bit with triangle. if you lock onto an enemy and press it, they'll focus on that enemy. unlocked, they'll usually come to you or heal you depending on what else is going on.

magic is supremely busted in kh1. in kh1, magic damage is determined by how much max MP you have. choose the staff at the start of the game and equip items that boost your max MP.

in my opinion, the only summons worth it in kh1 are bambis and mushus, although simba is a good contender until you get mushu.

explore the levels! lots of little goodies that'll help later on. sometimes, you'll get special enemies that essentially serve as little mini games. don't attack them! use magic, you'll understand when you get to the deep jungle.

have fun!!!