As I only really use my Balance Wizard, I can only give you the optimal combinations for that School. Submissions are accepted for other Schools.
There are three basic types of combatants: the Stallers (who focus on defense), the Strikers (who focus on offense) and the Synthesizers (it's not the best name, but I needed something beginning with "S" for continuity; these combine [or "synthesize"] offense and defense).
Stallers: Put five TPs into Ice for TowerShield. Then, invest seven TPs in Life for the Satyr Spell. Skipping on down to get a few Dispells may not be a bad idea; nor would getting a "reduce Threat" Spell. From the Star School, Auras that focus on defense (such as Fortify) would be a good idea as well.
Strikers: Seven TPs into Death will get you the Feint Trap, the most powerful Trap in the game. Put six TPs in Storm up to Kraken. Getting FireElf from, well, Fire will get rid of those pesky generic Shields in a jiffy. Star School Auras focusing on offense (such as Amplify) and Sun Spells that increase Damage may be Spells you'll want to boost your power.
Synthesizers: Get the Feint, TowerShield, FireElf, and Satyr Spells. A smattering of Sun and Star Spells would be a good idea as well.
You forget to mention the fourth type of player, and for continuity, I'll go with Somewhere Else. These players have spells galore but go AFK in battles.
