Puppy Kindergarten class is recommended to start your puppy off on the right paw. Ask your vet if his vaccinations are good enough yet to participate, then sign up when your vet says he is ready. One of the most important things he'll learn in puppy K is bite inhibition training.
Puppies are naturally exploratory. They like to pick things up and carry them and otherwise manipulate them. Since they don't have hands, they use their mouths. Some dogs, such as retrievers and German shepherds, are mouthier than others. It starts as curiosity, not aggression, but can become aggression if not handled properly in youth. Its important for all breeds to learn bite inhibition in order to interact politely with people.
You can do your own version of bite inhibition training by yelping dramatically each time his teeth touch you. The objective is to convince your pup that human flesh is very sensitive, which being bald, it is. Drama is key. Yelp and then shun. Turn away and refuse to look at him, pet him, or acknowledge his existence for one full minute. If he bites again, put him someplace safe where he cannot reach you, such as a laundry room, play pen or crate. Putting him outside is probably not a good idea because he may learn to bite when he wants to go outside. The difference is that outside is interesting and the other places are rather boring.
It is very hard to teach a dog a negative or to not do something. It is easier to teach him to do something else instead. After the shunning suggest the alternative activity to nipping.
Teach him about toys. Carry an assortment of appropriate puppy toys in your pockets at all times. When he shows interest in nipping, invite him to play with the toy instead. Some breeds like German Shepherds have strong prey drives, and probably enjoy chasing and pouncing. Try toys you can toss, like balls. If your puppy will be around smaller animals or children, avoid sqeaky toys. Small animals and children may shreik when frightened so avoid reinforcing associations between squeaky noises and prey drive.
What he needs to learn is that you will play with him WITH a toy, but not with his teeth on you. Make his choice one of "play with me with the ball, or don't play at all."
I give my dogs a marker to indicate when they've lost a chance to play. I tell them "game over man." Eventually they come to learn that that means the game has ended because they've broken a rule. When I end a game because I'm tired, or they are; then I tell them "Good game! Let's go get some water!" and I say it enthusiastically. If you notice, I'm redirecting instead of just stopping the game. Usually a drink of water is sounding good by that point, so they aren't too disappointed the game is ending.
Now what if he absolutely refuses to play with a toy instead? You might try a mild aversive, such as firmly saying "No!" picking him up and putting him away in his safe but boring place. Pushing him away is probably not a good idea because he may think it is a wrestling game.
Other mild aversives include a spray between they eyes with a plant mister, a startling noise such as tossing a shake can, or gently pressing his cheek inbetween his own teeth so he feels for himself just how razor sharp puppy teeth are. Immediately follow an aversive with an offer to play.
Many dogs grow up to be powerful, intelligent, easily bored dogs. They require exercise and mental stimulation. Think about what they were originally bred to do: Herd sheep? Go hunting? Burrow for small game? Draft? Guard? Herding, for example, is like playing chess all day long, anticipating the moves of their opponents (the sheep) and literally trotting for hours each day. You'll have to take up the slack and provide the stimulation that a job would provide him. Research your puppy's breed, and consider what his original job description was. Take those factors into consideration when training your puppy -- ideally you will provide games and teach him skills that simulate that job.
Perhaps you jog or cycle and he could come along. My old standby is to play fetch every day so they can run after the ball. Remember: A tired dog is a good dog. For mental stimulation, start with some good obedience classes. But it won't end there. You'll need to continue training throughout the dog's life, because they are easily bored and bored dogs destroy property or otherwise get themselves into trouble.
Stock up on books of tricks to teach your puppy. Join a dog club and participate in sports like competition obedience, herding, agility and tracking. Find small jobs for him to perform around the house. My dogs pick up things and hand them to me when I drop them. They find things and people by name. You can even use them to messenger other members of the family by carrying notes to them. I even taught one to start the washing machine. As with human juveniles you have a choice: Give them a job or watch them turn into delinquents.
Also check out this article by Dr. Ian Dunbar: http://www.jersey.net/~mountaindog/berner1/bitestop.htm