I learned a great trick at puppy kindergarten and thought this would be a good place to share it. The teacher said that when your pup starts playing with you as if you're a pup [biting], to react as if you ARE a pup when it hurts ... you YELP! A sort of high-pitched "ouch!" does the trick. She said you want your pup to think you are the most
sensitive pup around. Gradually, your pup will "soften" his bite with you as he learns over and over that you are such a wuss.

All pups will bite - it is how they play - we just need to teach them a
soft bite when they play with us. We'd been doing time-outs with Quin and it was pretty effective. We would physically reach in and remove Zoe (our 3 year-old) from his x-pen when he got too rambunctious with her. But the yelping seems far more effective. And Zoe is quite good at emitting a very convincing puppy yelp.