I've been teaching my dog how to roll over, he's a smart one so he's been learning fairly well but here's what I've been doing:
First get him to "drop", ie lie flat on the ground, then get a treat that the dog likes and hold it near his mouth so he can see/smell it while carefully turning him and commanding "roll over". As soon as he completes a revolution, give him the treat.
My dog can drop onto his back, anticipating the "roll over" command now pretty good, but he still needs a treat near his mouth to encourage him to roll over.
He also knows how to sit, jump and shake hands
