(Note: I'm not a professional artist)
This piece is great but, The neck is a little to long and the nose is a little to pointed.
the expression on the face is great! the eyes and hair could use a little more detail
and the outline on the image is too thick (for my tastes ). the chin is too pointed and the head is off placed compared to the rest of the body.
the color of the shirt is too bright (again for my tastes). the right eyebrow is too small compared to the other. Is you work on those your artwork will be alot better! ^_^