Hey, I tried to fix it a little bit so you can see what I would change in it, and I got a little carried away.
Some things I changed: The skin color was too orange, the eyes and lips made her look like a fish, the hair was too shiny, the arms were too thin, the hips were too square-ish, the legs were too short.
I hope, somehow, it can help you.
You have too much symetry! You should consider changing it up a little bit. Its kinda hard to determine where the light source is located... Changing those 2 things will improve your work significantly in my opinion. Good work otherwise, your lines are pretty smooth.
Long story short - study up on Anatomy. It'll be invaluable :)