It's like she's playing notes which are revealing themselves as visible colors, just like synesthesia. And of course the shading is awesome. I've been learning what I can from your tutorial you put up recently so I can become as good at shading as you.
Great pic overall. But I'm gonna be that one guy to point out something wrong. At the end of the bow, there's a little nob that turns to tighten or loosen the hair by moving the frog (the grey part in this picture). [link]
WOO. Hey...I've started doing art trades, and a comission, and since I've noticed that you also do them, is it bad to feel guilty about lateness of the comission/art trade because of lack of inspiration/being busy?