Well, for tips regarding head throwing, you need to remember that a head is actually quite heavy, and will seriously shift your center of mass. In other words, you need plenty of leverage/counter movement if you want to throw a head farther than half a meter. Legs, especially, help with this. If you brace your feet against the ground, you can throw the head pretty far. Also, proper elbow/wrist movement is also key, as a constantly extended wrist will make it very hard to extend/contract your elbow properly, especially extend. Contracting your wrist a little when throwing, then extending it about halfway through can provide a significant speed boost to the head, not to mention more power.