Children start learning right from the start as the brain starts developing. Although they cannot do much themselves, they see others actions and learn from them. Talk to your baby with a smiling face, introduce him to people in excited tones and respond to him while he is crying. These are the basics of socialism when you talk to the baby and show love so that in time he can do the same.
Babies usually reach out to everything as they have no sense of ownership but put other's belongings out of his reach. If a baby receives love and consideration only then can he spread them when he grows up. It is often noticed that babies who grew up in company of talkative cheerful people developed those traits naturally. The more interesting people he meets and the places you show him, the more exposure he is going to gain.
Let him explore objects and areas around the house and talk to him during it (ofcorse keep away from electrical or other dangerous objects). Teach a toddler to be gentle when touching objects and people. Teach him to be patient for food and toys and reward him if he keeps his control. Be kind to pets in front of him and to people who are disabled and disadvantaged.
In pre-school, teach the child to share stuff with his friend. However also teach him that he is to tell you or his teacher if he is being bullied int giving his stuff. Kids by this age should have strong sense of ownership starting from toys. Buy him his own toys but invite play groups from neighbors or friends and ask all the children to play together.
Let him attend phone calls from grandparents and other relatives and teach him the right way to address the call. Try talking to him about why he made a specific friend and over looked others. What values appeal him into friendship. If he is very negative about a certain kid in school, try tone down that negativity by telling him that ignoring and forgiveness are the best things for a gentleman.
The more you talk, the more expressive your baby becomes. Keep him away from crime or action movies/pictures at this point. Make it clear that all grudges should be addressed verbally and not with force. Host birthday parties and social events at home and invite their friends so that they learn the art of organizing. Ask them to make the invitation cards and post them no matter how childish they are. Children by this time should know the consequences for being rude and manipulative. Teach them morals by story telling. Teach them the basic 'sorry' and 'please' etiquette. Let him introduce himself to guests.
Take your kid on sightseeing tours even if it is around you own city. However this time explain to him the importance of all the buildings and interesting facts. The child will have something to tell his friends when they pass through those places in the school bus back home or school trips. Watch story books to him so that his imagination is strengthened and he can narrate stuff to people. At this point in age, you and his teachers are the best examples for him. Try to be a good moral exapmleIf you respect people and greet them nicely, your child will do the same. If you show empathy, the child will learn to do so. when the child tells you about a problem at school tell him a positive solution and explanation. Do not degrade his class fellows or teachers in front of him. Teach him the art of competition by correlating it with the amount of hard work and letting him congratulate the winner.