It depends if you are going for realism or artistry (or both) in your clothing. Doing realistic clothes is a mix of natural artistic ability and practice, practice, practice. I think your image is very good tho..not terribly realistic, but quite convincing as clothing. Don't forget that clothing casts shadows on the body, so make sure you add shadows to characters body where appropriate (you can mask out clothing layer and apply the shadow in a lower layer).