Since you are already getting the puppy, my best advice is to SOCIALIZE like crazy, with both adults, children and other dogs... and I think this can make a big difference in the temperament of dogs who are often feared by the public for their reputations -- Dobermans, pit bulls, rottweilers, wolfdogs, etc. Let many people play with, pet, cuddle, and love the puppy. Let the puppy play with other well-trained dogs who are tolerant of puppies, this may help him learn to not be aggressive toward other dogs, and he might even imitate and learn from the behavior of the older dog. NEVER keep him on a chain or leave him alone for long periods of time. Ideally someone should be at home to watch him practically all the time. I know this is not always possible, but being lonely and bored leads to all sorts of problems, especially for a large breed dog. Also have him fixed as soon as possible. Obedience classes will help A LOT if you can afford them!