Do you hop around when your puppy nips at your heels? Stand perfectly still (even though it may hurt) and say the firm "NO" in a deep voice. Puppy is just playing a game, and your actions have to tell puppy that you're NOT going to play this game. That goes for the hand biting also. If puppy wants to bite your hand, put 2 or 3 fingers in it's mouth vertically,( or a fist if the puppy is big enough) and put your other hand on the back of it's neck, so it can't get away. Leave the fingers in the mouth until the puppy gets uncomfortable and starts to squirm....it doesn't take long, usually. Then take your fingers out of its mouth and offer your hand. You will usually get a lick at this point, rather than an attempt to bite. Praise your puppy like crazy, tell them they are a good boy/girl. 2 or 3 repititions of this will usually solve the problem. Good luck.