[Disillusionist]

Ah good, because that seems to cover an idea I'd forgotten, Environmental components.
It's day or night, and that's a spell component, or modifier.
It's moon-based (the two games I've played recently both have three moons), or planet based.
Or they can only be cast in rooms tagged 'exterior' like Ranger or Druid spells, or need to be done in the presence of plant/organic items growing naturally, or near a body of water, etc.

One of the games is very item-intensive, which made no end of problems, what with inventory caps and an incredibly buggy command queue, so I -strongly- suggest that a lot of the juggling be abstracted.
For instance, 'prep spell' auto-picks the component, deletes it from inventory and emotes the proper manipulations abstractly. A flag added to be sure the character has one free hand (and that the component container is open) might simulate the juggling effectively, and the time-lapse can be emulated in RT or pause when >prep is engaged.

Assuming that 'schools' means the same thing as 'circles', 'spheres', 'elements' etc, some component ideas would naturally flow from the world's uniqueness. If one school is fire, perhaps just open flame nearby of any sort could be a component, for instance.

Not knowing how quickly combat, especially PvP, is accomplished in your game, I'm hesitant to post other ideas. Perhaps a short overview of round-to-round time-lapse, an idea of the ranging system if any, or the Gygaxian model of 'too much nearby metal foils magic' would make suggestions for your particular game more on-target.