What you really need to work on is perspective in your drawings. Alot of problems I see that you have are in that when you draw a face, the eyes aren't lined up, the face is too long, the shading, although implemented correctly, is messy, and the long neck, for some reason, looks like it blends into the background. This can all be fixed with having a simpler art style (just for now, at least) and learning how to use construction lines.