Expose him to new things. Take him out for walks every moment you can. I can't stress enough how important it is to socialize your dog now at this age. We thought we socialized Kai enough as a pup cause we were always going to events and such but he's still really timid of people and busy roads.

And work on obedience with him. I find that it's easier to tire out a dog mentally than physically (especially those puppies! I don't think I've ever been able to physically tire out a puppy). When my boys are acting naughty, we practice obedience. A tired dog, is a good dog. We practice obedience everyday just so they're satisfied. Who knows, maybe it'll save his life one day. Kai's sit and stay saved his life many times already.

When new people come over, have him on leash but the moment he jumps up on someone, you can snap the leash, use a water squirter or anything to let him know that that's no allowed. For Kai, we ignore him when he jumps and wait until he sits before he gets praise from the visitor. For Kaedyn, he has to down and stay or else he gets a squirt. He's very nippy with new people but this has worked really well with him.