Practice

Head is a little bit too small for the body. However good job on not making it too big. Lots of people do that, including myself.
Shoulders are also too close together, unless you are going for a very pear shaped body. Collarbones are wider than people think and there is more room from the neck to the shoulder than people would guess.
That being said, it's an illustration, so it depends on how realistically proportioned you want to go, or if you're going for more of a style that carries an exaggerated pear shape.