I agree with scarlethue, the thickish lineart doesn't seem to work well with the soft coloring. Either cell shade instead, or just use thinner lineart that breaks up in some parts. Another thing is that the nose and it's shading looks quite awkward. I suggest you look at how a nose looks at that angle first, then I guess manipulating it to fit your style better.

The BIGGEST problem is the angle of the head. I see you're trying to make it so she's facing up, but her facial proportions, her neck, and her chin does not match that angle. Take a look at these refs. I included a manga ref because it's not really easy to emulate realistic proportions in a distorted style. But if you notice, this artist still uses realistic proportions in the angle. Please don't just copy the lines of the drawing, as well. Look at the photo and understand how dimensions work and how there is a skull under that face. Seriously.



SPOILER! :