Take him as many places as you can, expose him to all kinds of different things--traffic, gravel, grass, pavement, people, kids, other dogs, everything you can think of.

Do you have friends with dogs? Arrange playdates--your own personal puppy class!

If he acts scared of something safe, DO NOT reassure him. You continue to act like everything is fine and he'll follow your lead. It's really hard not to cuddle them and tell them it's ok, but that only reinforces the fear. The more things you can expose him to now as a puppy, the better adjusted he'll be as an adult.

I have several dogs here who received no socialization as puppies. Socializing an adult dog is extremely difficult and the results are limited. Do it now and do as much as you can. There is no such thing as an oversocialized dog!