[Crazy the Clown]

To bulk 'em up, I'd just fight against weaker foes, and kick my own ass, but almost never to the point of death. Sometimes, it's unavoidable.

To build their magic up, I'd take the top 3 and use a method I learned by reading a cheat site's info. Goes a little like this.
-First, select a spell, and confirm the selection. Doing this will bring the cursor to the next fighter.
-Next, take back your command with the cancel button.
-Repeat.
(Note this doesn't work for Leon, Layla, Gordon, Mindu, Josef, or Gareth.)

To build their weapon skills up, I equip each character with 2 weapons at once. Sometimes, I use 2 different weapons, so I can build up 2 different weapon types, simultaneously.