Their are many things needed to be worked on here, but two of the biggest is your underlying structure and your "editing."
Yes you need to work on anatomy over all, but I think getting a good grasp of the skeletal structure underneath the character will be key in bettering your works.
By drawing a very basic an simplistic skeleton you can begin to see where the muscle structure and thus the skin, needs to go. Your shoulders are really awkward, and your head and neck are way off.
As you begin to get a grasp on the anatomy, proportions will begin to follow.
As for the editing. It looks really bad. I can see you were attempting to remove and/or recolor parts of the background. The cut work looks very rough and you would have been better off using maskes in Photoshop or the free alternative, Gimp.
You could use a little bit more defined linework and some more solid colors as well.
At least you strived for a more interesting pose and some post work. So I give you some props for that. Keep practicing and better luck next time.