I like to keep a familiar summoned when I practice magic, I think it gives an xp boost. Also, if your Sim reads a lot or talks about magic a lot, I get the perks to passively give caster xp for that too. Also, experimenting at the cauldron helped me max out fairly quickly, as well as once they learned the spell "Transportalate", I set them to "Always Transportalate", since that gave them points as well.
Also, instead of showering, Scruberoo! Dirty counter? SCRUBEROO! Broken sink? I use repairo. Hungry? Delicioso (or whatever it's called, I only just got that one haha)
I use magic for as much as I possibly can as a spell caster. The perk to empty your charge meter is a huge help!
