The first thing that came to my mind was to maybe make the skin a bit brighter. And since the image is more in the midtones/dark values it would have the added benefit of pulling the viewer towards her face. Then you could also darken the hair which would frame the face and pull the viewers even more towrds the face. Or you could instead lighten the hair. I think it could look pretty cool.
Here's a quick paintover I've made to show what it could look like.
Lighter skin+darker hair and armor:
Lighter skin+lighter hair:
Anyawy I'm really liking the direction you're going with this picture. I'm looking forward to see how it evolves!