Good use of color. I like the mood it sets and the posture of the model. The hair is excellent. My general opinion? Wow!
Improvements? The head looks a little flat. The forehead feels like it ends prematurely. The iris blends into the background quite a bit. I'm not sure if that's intentional or not. As in, it looks unintentional. I'd suggest making the iris dark brown or some other color that'll make it pop against the background. If the eye were looking at the viewer, that may also improve it.
Oh! And the red spots on her cheek nose are a nice touch. They give the general impression that it's chilly where she is, or that perhaps she wears glasses (since the red mark on the side of the nose is the mark a person might typically have if they wear glasses often.) The texture on the jacket is also nice, though it does get blocky and a bit "unfinished" looking in places- especially the arm- but that could just be the style.
The back of the neck where the collar of the jacket and the hair meet is really *really* well done. There's a nice sense of folding and weight there.