I have just gotten my first dog, a very cute Labrador puppy. She is a bundle of energy and always wants to play, when she is not napping that is! Only problem is, she has started to bite me. She is so small that it doesn't really hurt, but I figure that she won't stay small for long so I should probably stop her from doing it, sooner rather than later. She is not being aggressive, just playing a little too rough.
Firstly, don't worry too much about your puppy - nipping etc is a very common behavior. You are right though - the sooner you get her out of the habit, the better. When puppies are still with their littermates, they teach each other "bite inhibition", which basically means that they yelp when another puppy bites or plays too hard. All of the pups quickly learn how rough they can play without hurting each other. You can use this example to teach your pup that her nipping is not OK. Next time she nips you or plays too rough, you should yelp like a littermate would. Your pup will probably stop what she is doing, giving you a chance to praise her. If she ignores the yelping method, you could try giving her a time out. I have a cat who used to pick fights with our other cat, and giving him a timeout was a great way to get him to settle down. It also worked on our dog when she was misbehaving. Good luck. As I said, it's totally normal for your pup to behave this way, but if you are consistent, and don't let her away with it, she should get the message.