You should start training your puppy from the first day that you bring him home. It was once thought that training shouldn't begin until your dog was at least six months old, but this was when trainers relied on punishment methods that might injure puppies. Now that most trainers use positive methods, training can and should begin right away.
Socialization
In the first 14 weeks of your puppy's life, he must be exposed to everything of which you don't want him to be afraid later in life. This includes children, men with beards, gardeners, vacuum cleaners, skateboards and other dogs, just to name a few. It's your responsibility to teach your dog to be comfortable in your world. This begins immediately.
Even if your puppy hasn't been vaccinated, take him out on your block, to a park, to a pet store or elsewhere, and don't set him on the ground. Hold him to prevent him from coming in contact with the viruses your veterinarian fears. Have a pocket full of treats and reward your puppy each time he shows interest in something new.
If your puppy reacts or tries to hide, don't punish. Follow his wishes. Don't make him get too close to anything that seems frightening. Stand far enough away that your puppy isn't afraid and reward. Maybe next time he will be able to get closer.
Potty Training
A potty training routine should also be established immediately. Start getting your puppy used to his crate as soon as you bring him home. Use the crate to keep him confined when you can't watch him. This will prevent accidents. If your puppy never gets the chance to use the bathroom in your home, he never will.
Anticipate when you think your dog will go. Lead him outside and reward him for going. Wait a few minutes to make sure he doesn't have to go again. If you ever see him sniffing around, rush him out again. Don't punish for mistakes. Just be faster next time!
Polite Behaviors
When your puppy is only a few weeks old (as soon as you bring him home), he can learn not to jump and nip. Your puppy can learn to sit at a few weeks old. Just hold a treat over his nose and move it slowly toward his butt. As he sits, say "Sit," praise and reward. Ask him to do this rather than jump. Ignore all jumping and reward all sitting.
You should also start teaching your dog immediately that he can't nip by yelling "Ouch" when he puts his teeth on you and then storming out of the room. Offer him a toy that he is allowed to bite.
Additional Training
While some commands, such as "Stay" and "Leave it," are difficult for young puppies and should be taught when your dog is closer to six months, other commands should be taught right away. Recall is one such command. Teach your dog to come when called when he's a young puppy because at this age, he is less independent and more likely to come right away anyway.
You should also teach your dog how to lie down, accept handling and walk nicely on a leash when he is only a few weeks old, and thus can't overpower you if he doesn't want to do something. Teaching your puppy commands at this age will help him develop into a well-mannered adult.