Alright, I finally got around to her again. Im going to try and keep working on her until she's completely finished ... which is a bit of a step for me, as I never finish anything I start drawing, it seems.
I was trying to go for water reflections on her skin (thus the blue/greyish color), but it turned out a little muddy. And Im not liking her hair ... the shading most of all ... it seems to not be as smooth of a gradient as I'd like it to be.
If you can, I'd suggest colouring the lines darker colours of the shapes they surround, instead of letting them remain black. The black feels a little harsh, especially given the saturated colours you have here.
If you have the lines on a separate layer (and if you are working in Photoshop), I'd suggest locking the layer transparency, and painting on the lines. (If the lines are on a black/white layer, you can get them extracted mostly by grabbing the alpha channel on them.) Colouring the lines will soften this piece up.
re: The hair - Currently it feels a little plastic, because you are rendering and lighting it as if it was one big piece, instead of a lot of little pieces. It's tough because you've made a stylistic choice, but I'd consider perhaps trying to go for a cel-shaded type of look, and then maybe softening random edges with a blur or smudge brush.
I worked on the hair a bit. Made it into separate strands, kind of, instead of one giant blob of hair.
I tried coloring in the lines, but I really didn't like how it was turning out, so I ended up going back to the original. I was, though, turning the layer with the line art on and off again and again, seeing how it looked .. and I think I might be able to make this girl work completely without the black lines, especially if I just tweak it a bit here and there.
I'll try and work on it some more today ... We'll see how it goes.