Wow. There is some of the worst advice on here(minus Mrs. Cos and Mike).
You should never, ever hit a dog. It's not going to correct your problem, neither is flipping the dog and showing them that you're "alpha". People watch Cesor and think they can do it to every dog. Those are last resort styles of training, being the reason why every dog on that show is severly aggressive.
You should show positive reinforcement when the dog is doing what you want(treats, toys, attention). If the dog is chewing the couch, you just redirect them to a toy that is safe for them to chew(ie Kong). Then while the dog is playing with said toy, you should show them positive attention(ie belly rub, pet them, a "good boy/girl").
My wife is a trainer at the Petsmart in Hilliard (soon to be Grove City), but the classes are 8 weeks, 1 hour per week and they cost $109. About $12 a week, and you'll truly learn a lot.
If you have any other questions and you want real answers, not some retard that's going to hit their dog, you can PM me or call and talk to my wife.