How to stop my dog play biting?
You need to teach him not to bite. This is normally learnt through play fighting with the rest of the litter but in the absence of canine companionship you'll have to take up this duty.
Consistency in your response here will really speed up his understanding of what you want to achieve. Every time he nips you, let out a loud, high pitched yelp, turn your back and walk away from him. Don't scold him.
How you behave will have an incredible impact on the dynamic between you and your dog, remember that dogs are by instinct pack animals and will behave as such. If the dog comes to view you and your family as subservient to them you'll find it incredibly difficult to readjust the dynamic without causing grief.
Be dominant and decisive in your actions. Make sure that it is you who lead the pack and enforce this hierarchy at every opportunity. Little things such as making sure that the family eat before the dog and not letting over-zealous behaviour gain attention will all contribute to your dog's sense of position within this structure.
Don't be aggressive or rough with the young puppy as this will reinforce this behaviour, if your puppy nips you let out a high pitched yelp and stop playing with them, this is what their litter and mother would do. The best way to avoid poor behaviour is to pay it no attention. If you make your puppy realise that chewing shoes and barking at the door isn't a game that you want to play with them they will soon catch on.