My trainer just had me working on this on Sunday and it felt pretty powerful and fast.

From the normal boxing stance begin twirling your hips counterclockwise while simultaneously jerking your right leg straight (vital). Your hips will rotate completely (also vital) to give it the proper snap. Your forearm extends only until perpendicular with your upper arm. Your elbow will rotate up.

I hope I explained it right. I never liked the right hook until my trainer showed me and now I love it.