Puppies LOVE to play - that's what they live for. What's the worst thing that could happen to them? Play ending. So that's how we will "punish" them for being too rough - by suddenly making play stop when they bite. The rule is "All fun and games end when puppy teeth touch human skin".

Pups bite because it is fun, it's their way of playing, and it gains them attention. So, to punish the puppy, all we have to do is make the fun end. If you're playing with your pup and his teeth touch you, yelp loudly and shrilly like a hurt puppy. (If this makes him MORE excited, or if you're a guy who can't really do this, BELLOW like he's really hurt you). Immediately disengage yourself from him, and as calmly as you can, leave the pup behind (in a safe, puppy-proof place). Give him the cold shoulder. You only have to leave him for a little bit (less than 5 minutes, probably).