When i looked on this picture i felt that something in anatomy is bad. But it took me a time to find out what's the problem.

Fistly, your curves are not confident and smooth. I recommend you to draw lines by rapid movement of the hand. This recommendation also applies on black shadows you've drawn. Also it's good to do thick and thin lines when you are doing lineart. It looks much better when you "pop-up" pieces of picture. It makes depth.

The next thing i've found incorrect is her right (from our view left) leg, breast and head. Leg is a bit off, head is unproportional and breast should be higher. In this picture i tried to show it: http://www.newgrounds.com/dump/item/d3c6a94b78af95564336e37b79766362

So.. i hope it helped you at least a bit :) Practice more and draw often, you have potencial. Good luck in your journey ;)