Feedback: 1. Heads are not some weird shape, they are ovals. 2. Draw lightly and sketch. They less you erase, the better. 3. With heads being ovals, hair is only like half a centimeter around the head.
Whenever I draw something I haven't before I tend to look up reference images to see the body proportions and things like that. I'd say try drawing more and you'll eventually get there.