When socializing your puppy, remember to ask politely before letting your puppy approach another dog or person. Not all dogs or people enjoy such interaction. In addition, ask before you take your puppy into any building besides your own house.
Many people will also approach you to touch your puppy. Encourage this behavior, but if people touch your puppy without asking, take the opportunity to cheerfully remind them that, for safety's sake, they should ask before touching a strange dog.
Many lasting friendships happen because of interactions with other dog owners. Puppy socialization can also mean great socialization for you!