Cute, I'm really liking your style. More good work with lighting and pose in this one, and the background contrasts the clean lines nicely. However, the gun seems a little short (whatever) and flat (which is a problem).

I don't know if you just got lazy with/rushed the gun, but it seems to have less depth than the rest of the picture. The shine on it from the butterfly is an awesome little touch, but other than that, it's just lacking little stuff that would make it pop. If you are looking to improve your depth, I'd look at "Dancing notes", your work with the notes in that one is definitely on the right track. There is, however, some decent work with depth on this piece, especially on her left arm.

Conclusively, it's a nice little piece for what it is. I'd also like to note that there's certainly more good to it than bad, but I'm not too skilled at critiquing the good.