Rescue dogs come from a variety of backgrounds but all dogs can do with more socialisation. After your new dog has had some time to settle in and he is showing some confidence in you, give him lots of pleasant social experiences. He should be able to meet people (and other dogs, if he's not dog-aggressive) at home and near home. Then perhaps in new places like parks, obedience school, etc.
Try to make sure that you allow your new dog to be handled by other people only after he has a chance to trust you. Then gradually do introductions to other people. Family members first, then friends he knows. Introductions can take the form of giving the dog treats, petting, playing fetch, even going for a walk with a trusted, dog oriented friend. Do not force the dog to accept people, allowing HIM to approach people, rather than people approaching the dog. Use treats and have patience if he is reticent to allow other people to touch or play with him. He'll usually come around with time.
At first, be sure to tell people NOT reach for the dog right away. Let him come when HE wants to. If he doesn't, the visitor should completely ignore the dog. Suggest that after the dog has met/sniffed the new person, that they pat the SIDE of the dog's neck or side of shoulder. Patting the top of a dog's head is interpreted by dogs as a dominance attempt and can issue a challenge to some dogs or frighten others. Most dogs have no problem with this but since some do, it is always best to exercise caution.