I get a lot of phone calls about biting puppies. Most people are using the old technique of yelling at their dogs or grabbing the dogs muzzle as they yell at them, or worse, hitting the dog. I just got done with the biting puppy experience with my own 6 month puppy. She was actually given up for adoption because she bit so much. How did I solve it - very easy!
Puppies are experiencing a lot of pain as their new teeth grow in. The best thing to do - give them lots of natural things to chew on. Ally Mae, our puppy, just discovered a complete love affair with Marrow Bones which can be bought at a butcher shop. She adores Elk Antlers and Deer Antlers as well as Buffalo Hides that take her days and days to chew. When we first got her, I would keep Marrow Bones in my pocket because when I petted Ally Mae, she would bite. She was not mean, she just did not know how to interact with me. As soon as she bit, I would give her the Marrow Bone. The other safe bet, is to have no reaction. I don't want to turn into a squeaky toy for my pet. She learns quite quickly that my hand is really boring but these wonderful chewy toys are great.
Common Sense training is what I do - fulfill the need of the puppy to chew and you have a winning combination.