As soon as your puppy has had his inoculations and can be taken out, it's a good idea start to socialise him by introducing him to other people and other dogs.  An excellent way to do this is to attend puppy socialisation classes where he will meet other puppies of a similar age in a safe environment.  Your vet will probably know when and where these are held if they do not run them at the practice.  You will also probably be given information about looking after your puppy including information about parasites such as worms and fleas.