Socialization:

Even if your puppy hasn’t completed all of his vaccinations, it's important that he meet other dogs and people. Get together with friends who have healthy, vaccinated dogs. Have people over - all ages, races, with and without beards, with and without hats and coats, etc. Get him on various floor surfaces, in an elevator, around traffic and bicycles. You get the idea. If you have a fearful or timid puppy, don’t force him into a situation that makes him uncomfortable. Whether your puppy hides or lunges, don't yell, punish or yank at his leash. Think of it as a signal that you'll need to help him develop good associations with whatever he reacted badly to. So, next time, give him pea-sized treats in rapid succession the entire time that he is around what frightens him. Socialization can only have the desired effect if your puppy has GOOD experiences; bad experiences can create fears and anxiety. So, supervise your pup closely and don’t put him in situations where another dog, stranger or child could bite, scare or harass him.

Resource Guarding:

Some dogs growl or bite when things are taken away from them (toys, food bowls, bones) or when you get in "their" space (on the bed or sofa).  They should learn not to guard resources as puppies, so it doesn't crop up later. When you feed your puppy, go by after a few minutes and put a really good food (maybe chicken) in the bowl.  After a while, pick up the bowl before he is finished eating, put chicken in, and return it to him.  He will get the idea that if you take something from him, he can expect something even better coming back.  If your puppy grabs something you don't want him to have, don't chase him.  If you do, it's a game.  Instead, go the opposite way, so he's chasing you, and trade him for something even better.  I want my shoe, but you can have this yummy chicken. The space on the bed/furniture issue is more a problem of how much he is treated like king of the house.  Little dogs tend to be spoiled more than larger dogs, and they act like it.  You can prevent this by asking him to do something for you before you do something for him. Once he learns to sit, he should sit before you feed him, give a treat, put on his leash, play, enter or leave the house or car.