I like the style and the concept. I think with the hair though, there needs to be a tad bit more of a highlight. The shadows on the body are fine. And that outfit looks amazing.
The only small thing I don't like about this is the background color. Maybe just a tiny bit darker and that would really make those wings pop out. For glow seems to be kinda lost. Not unless you wanted them that way. lol
Hope this helps a little. But I really do love this image.
You are probably right, I think I ended up going too subtle with the hair. On my laptop there is a lot of hair detail- When I look on mobile devices and at work 80 to 90% of it just doesn't show. =/ The background is a tad lighter than originally planned. I lightened it to try and better balance things but I could have gone too far. I do have an alternate version on my desktop where I had been playing with these changes and others. Thank you for commenting!
The only small thing I don't like about this is the background color. Maybe just a tiny bit darker and that would really make those wings pop out. For glow seems to be kinda lost. Not unless you wanted them that way. lol
Hope this helps a little. But I really do love this image.