It is very important for your puppy to learn not to hurt people well before he is three months old. Ideally, by the time he is four and a half months old (before he develops strong jaws and adult canine teeth) he should no longer be exerting any pressure when mouthing.

Focus is the single most important command to teach your dog before any basic training. If your dog is looking away from you, he is listening to what he is looking at. Distractions are a large part of life, and you need to teach your dog to ignore them and pay attention to you.