Try adding a lighter area on the right of the main part like Lexou did, and maybe darken the main "dark" shade of the body part and I'd say you're set.
EDIT: Oh, and try smoothing out the window part on the left. By "shortening" the top left area it should be more circular.
EDIT: Oh, and try smoothing out the window part on the left. By "shortening" the top left area it should be more circular.