Every dog needs to learn to walk on a leash. Besides the fact that most areas have leash laws, there will be times when keeping your dog on a leash is for his own safety. Learn how to introduce your dog or puppy to the leash, then teach him how to walk properly on the leash, even beside you on a bike. A loose leash walk teaches your dog not to pull or lunge when on the leash, making the experience more enjoyable for both you and your dog.
When you're playing with toys it's the same thing: his teeth mustn't ever touch your hand. If they do you say "Ouch!", kind of the same way his little mates would, and turn away from him. So if you feel his teeth on your hand at all you let him know with a little "Ouh!", turn away and let the game stops for a few seconds. Make sure to speak up every time he bites too hard so that your puppy can learn your threshold for what is acceptable and what isn't. Then go back and play again but he has to remember not to use his teeth and to be more careful next time. dog training collar