Give honest and sincere appreciation
Every person you meet is superior to you in one way or another. So try to figure out the other person's good points. Don't flatter, but give honest and sincere appreciation. People will cherish your words and treasure them and repeat them over a lifetime - repeat them years after you have forgotten them.
Don't criticize, condemn or complain
Criticism is futile because it puts a person on the defensive and usually makes him strive to justify himself. Criticism is dangerous, because it wounds a person's precious pride, hurts his sense of importance, and arouses resentment.
Instead of condemning people, let's try to understand them. Let's try to figure out why they do what they do. That's a lot more profitable and intriguing than criticism; and it breeds sympathy, tolerance and kindness.
When you start communicating with someone, first think of the response that you want to get and what is the purpose of this interaction, e.g. - getting your way, making someone feel better, just have fun, etc.