Your use of color is wonderful! Her face and expression are my favorite part. Just a thought, her hair is a little distracting from the rest of the picture. It almost seems as though her hair is "in front" of her face and the hard edges don't blend very well with the "soft" or "flowing" feel of the rest of the picture. I realize that you might have been going for a specific "feel" or particular style, but just wanted to give some of my honest thoughts. I know I always appreciate it when people do that for me.
Sometimes with my own drawings I can't go back and fix them up... I just need to leave it as it is and move on to the next drawing with what I learned on the previous one - if you know what I mean. Hair is a very complicated thing, but it's one of my favorites to draw!