Wow, first time I'm writing a critique and it's to you, so be nice! Lovely pic of Symphony, I really like the colors you picked and the way you colored it with the white glowy dots and her shiny jewels. Nice cell-shading as usual. Her wings looks beautiful, I can tell you put alot of effort with all the details on them. And the idea of her playing a violin is neat, suits her well.

Anyway, what I think you can improve on is drawing hands. The hands seems to been drawn in the same angle. Her left hand looks strange, as if she's not really holding the violin and is almost dropping it. Her right hand looks fine, though I'm missing where her thumb goes so maybe if you drew the thumb it would be more clear that she's really holding on the violin bow with her whole hand. However, I suggest to try drawing hands in different angles.
Her face seems a bit long. Her nose and mouth are placed too far down on her face. Maybe if you tried to move it up closer to her eyes and move the nose a bit apart from her mouth it would look better?
And just one little thing, it looks like her right leg is disappearing behind her left, but maybe that's just me. XD

Well, there you go. ^^ I hope I could help you in some way and that I didn't sound mean or anything. Anyway, great work with pic! I'm sure *fortissimo loved it!