Puppies play with litter-mates by nipping and biting each other. Unless trained otherwise, their tendency is to want to play with you the same way. They need to be discouraged from playing this way with family members from the start. There are a few things that you can do to curtail this behavior and to stop puppy biting.
Consider if your puppy has had enough exercise. Puppies tend to get overly nippy when they have too much energy that needs to be expelled through outside exercise.
Consider if you or someone else is playing in a rowdy manner with the puppy. Children tend to play with puppies in ways that encourage them to bite and nip. Running around and playing rowdy will encourage puppy nipping. Children need to be taught how to play with puppies just like puppies need to be taught how to play with children.
When your puppy is very young, always keep a toy in your hand to divert your puppy’s attention away from your hands. When he bites your hands, move the toy around to attract his attention away from your hand. If your puppy isn’t interested in your toy, try another one. If he continues biting you, get up and ignore him.
Praise your puppy when he settles down to playing appropriately.