I love this piece! The positioning of the character, the wand, the magic effects behind him, everything! There are only 2 things I'd change if I were drawing this:
1. Re-position the legs so that there isn't a symmetry line between them (since he's floating and with the way the legs already are it seems as though he's standing on something).
2. Either make a mask on the line art to make the inking around the hair lighter or SLIGHTLY change the way the individual strands of hair are drawn since the realistic hair looks slightly out of place with the cartoon body.
I love this drawing!