Well first off you have a good eye for color and obviously have artistic ability. The biggest flay I see here is the line quality. When working with a simplified art form like anime or a cartoon style that is one thing you cannot skimp on. When I draw my initial sketches are quite rough but then I go back and to a clean line pass, as I call it. I think something like that would do wonders for you. You might wanna adjust that background so your character stands out more. Check my gallery for examples! Keep it up.