Everyone wants essentially the same thing in life and that is to exist and flourish. Living a long and fruitful life is a difficult thing to do when a person can't coexist with other people in harmony. Living in harmony not only helps others but it is helps the person living the harmonious life.
Talk about non-controversial topics with people. There are certain topics like religion and politics that can send another person into a diatribe at the drop of a hat. It is best to talk about movies, the weather or anything that does not lead to a confrontation.
Focus on the commonalities you have with other people rather than the differences. Most individuals can find at least a few topics on which they agree. Too many times a person can focus on what other people do not like or believe, and this can give them a negative opinion of others without even trying to find some common ground on which you do agree.
Listen to other people when they talk to you. Do not drift off or try to think of what you are going say in response. You will be surprised how much people appreciate someone who is really listening without judging or arguing.
Set proper boundaries with people in your life. Let them understand that there are certain conversation topics and actions that you do not condone. It is up to you to set the boundaries and make people adhere to them. However, do not be confrontational or argumentative about setting them.
Some people just cannot get along no matter what measure you take to make a relationship work. So just stay out of these people's way and let them live their own lives apart from you.