For play-biting, I like to simply say "ow!", pull my hand away, and not play with the dog for 5-10 seconds, then slowly play with it again.
The dog's main objective is to play. They quickly catch on that if they bite you, the play goes away - the only way to keep non-interrupted play is to NOT bite.
Another aspect of that is that if the dog ever play-bites anyone else, they're first reaction is usually to say "OW!" and pull away - and if that's what you've taught the dog ends up in no play, then his immediate reaction will be to STOP biting. Pure beauty.

My 11-month old dog, who will always be a puppy at heart, is VERY oral - he has always got to be doing something with his mouth. But he learned that way not to bite on people, and in the odd case that he does, if you say "ow!", he stops, sits down, leans forward, and starts licking your face, as if to say "I'm sorry, I didn't mean to!"
For growling, again - look at the potential reward that the dog can get from growling. He may want to play, he may want to chase something away, whatever - if the reward NEVER happens, he'll eventually realize that, and stop. Just remember, though, once he realizes that his growling isn't working any more, he'll growl MORE at first - but don't get frustrated, that's good! It means that he's starting to realize that his behavior isn't producing any benefit or reward. Just keep it up, and before long, he'll start giving up on the growling.
Dogs, like humans, are astoundingly good at realizing what behaviors get them the reward or benefit that they want - and they're astoundingly quick to stop behaviors once they've internalized the fact that it won't result in any benefit whatsoever. You just have to help them realize that there's no benefit.
steve