I'll start on a few basics:
-Is the Maguss-verse alternative (think High Fantasy), separated (think Potter) or superimposed (think The Doctor)?
-How popular and well-known is magic? How wide are the Orders?
-Are there Muggles and how are they called? (I propose Commons if there's none) How do they deal with creatures? Do they know of magic?
-Why is magic so addictive?