The trick to Donald is that his beak is really squared off kinda. Before I really understood the structure of Donald's beak, my drawings looked awful. When he is angry, his eyes are more like triangles than ovals. And he always has messy hair, which is more interesting than a plain round head. I really appreciate all the work that those animators put into Donald, he is pretty detailed for a major character. Oh yeah, and those eye arches extend above the top of his head.