No matter what you do, your puppy isn't going to stop biting overnight. Training techniques, however, can be used to eventually teach the puppy not to bite. Puppies and bite for a few reasons, including teething, exploring and playing. Puppies, unlike most adult dogs, haven't yet learned the skill of bite inhibition; this is what you must teach in order to stop the puppy from biting.
One of the primary reasons puppies must be taught to stop biting is that they were taken from their mothers too soon. Puppies shouldn't be separated from their mothers and their litter mates until they are at least 8 weeks old; 12 weeks is best. It is between the ages of 5 and 8 weeks that the mother teaches the puppies many social skills--including bite inhibition. The rough and tumble play of puppies in a litter also is part of the natural way in which puppies learn not to bite.
The most effective way to teach a puppy not to bite is to use the method her mother would have used. When the puppy bites, yelp--just like a dog would do if it had been hurt. The puppy may stop in surprise and then launch right back into play, biting again. This time turn to the puppy and growl, sounding as mean as you can. Turn away and refuse to play with the puppy for a few minutes. This sends the message that you aren't going to play unless the puppy plays nice.
Another method is to teach the puppy a command for the behavior you want. Hold the puppy's mouth closed for about 10 seconds. This training should be done when the dog is calm and in a quiet setting. While holding the mouth closed, praise the dog and tell her, "Close your mouth." As the dog learns the command, when she does bite, you can say, "Close your mouth." This will remind her that biting is not acceptable. Be careful not to cause the dog to bite her lips or tongue when you hold her mouth closed; hold the mouth gently and not in a way that is uncomfortable for the puppy.
Be careful of the games you play with your puppy. Many of the ways in which humans play with puppies actually teach them to bite. Wrestling with the puppy, especially with your hands, and games such as tug-of-war may confuse the puppy about when it is OK to bite and when it is not. It is best to avoid these games with your puppy, especially during the stage of development when he is learning bite inhibition.
Punishing your puppy--especially physically, such as swatting or slapping the dog--will not stop the puppy from biting. What physical punishment is likely to do is cause the puppy to become more determined to nip and lead to the dog biting out of aggression. In addition, physical punishment will destroy the bond that you are seeking to create with your puppy, causing the puppy to fear you.