Well, here some rules that I use:
Maintain your social relationships – Remember the names of people whom you want to maintain relationships with. When someone addresses you with your name, you’ll feel more connected with the person. If you can’t, do read up on what to do if you’ve forgotten someone’s names, there are plenty of textbook guides on that!
A light genuine smile when you’re meeting someone whom you have a relationship with. It is very easy to identify a fake smile from a real one. A genuine smile goes a long way into solidifying yourself as an approachable, trusting company. If you’re not feeling though, I’d recommend not to do it. Just a slight nod of acknowledgement would serve the same purpose.
Be interested in what people are saying. People love sharing their lives and stories. Let them share and just listen attentively. If you’re not interested in what they have to say, then they might not be the suitable company for you.
Be a man/woman of your word. This is the most important rule. This makes you trustworthy. People will look up to you and want to maintain the relationship with you on their own accord. So don’t promise too easily.
Hope that helped!