Nice work, I like the girl. She looks so lively and I like her style. I also like the background, even if the bottom of the right wing doesn't loot so detailed like the other one. But it sounds like it's still a WIP, so it's okay.
If you still work on this, I think you should watch that her dark head, doesnt go down in the dark of the background (^.~) And that last fold of her skirt at the left, which is only visible under her jacket, looks like it doesn't belong there. On the right side it looks like the skirt is actually not so long and I can't really imagine, how that fold is running. The rest of the skirt looks really good.
I'm not so sure about the shading. At the girl it looks like the light source is left. But the background goes in another direction. And the shadow the girl is throwing at the Background also shows, that the light must be coming from the right. But the sparkle on her jacket and the lightning on her hair and shirt, say it comes from the left. This looks a little confusing.
But allover, this is a good work. I'm looking forward to see the finished version. =D