One of the most important things that your rottweiler must learn is trust for you and also that the human hand is a friend. You're building the foundations of a new relationship with an animal with whom you've chosen to spend many years of your life. You want that relationship to be based upon love and mutual respect. To that end physical punishment or 'corrections' have no place in a successful relationship between you and your dog. To be effective, punishment must be given during the behavior and should only be intense enough to stop the behavior without causing any anxiety.
Timing is very important.
Don't rely on discipline to shape your pet's behavior but instead seek to reinforce desirable behavior. No discipline is effective without counterbalancing it with love, and praise while you reinforce what is acceptable within the home. It is essential to reward with food treats and praise at least as often as you discipline. All too often people reprimand their dog for inappropriate behavior and totally ignore reinforcing good behavior. You should actively look for desired behaviors so that you can praise your pet.