One of the best ways to train a dog to be obedient is to pick it up completely off the ground often.
The dog understands that you are much stronger, and when puppies are little their mother will pick them up in her mouth when they wander too far.
So as an adult the dog can remember that you are in charge because you can lift it up.
My friend has a 200 pound English Mastiff that he always picked up when it misbehaved as a puppy, and yelled at it while it was in the air.
The dog is pretty obedient for a breed with such a stubborn disposition.
He still does hit the dog if it shows aggression towards a friend or another dog, and I can understand that.