When it comes to socializing your golden retriever, it's best to start them out when they're young - socialization. It is a way to accustom them to the presence of humans and other animals; and it keeps them calm in the face of anything new or strange. The benefits are obvious - this makes future training easier, and it allows your golden retriever to live a stress-free life; without being under constant anxiety or fear should anything new or strange present itself to them or in their environment.
Socialization is really just spending time with your new puppy, and getting him accustomed to your presence. Gradually, you will introduce him to the wider world - on walks or romps in the park; where he will be introduced to new environments, new sights and smells, other humans and other animals. What he does need to learn at this point is that just because something is new; or strange does not make them a threat. He can freely explore the world and satisfy his curiosity without being overly timid or shy.
Socialization should be done as soon as possible, even if it is little things like you spending time with them. Most experts agree that there is a very small window within which puppies can be socialized. Any later than 12-18 weeks, and it would be very difficult, if not impossible; to get them past the natural timidity and caution of their puppyhood days.
In addition to the socialization training, you should now begin teaching your Golden puppy a few basic things, such as their name; to come to you when you call, the use of a leash and collar, and of course, housebreaking.