1) One’s dealings with other people should never be guided by cold reason alone, but one should always consider their frame of mind, that is, their character traits.
2) Everyone thinks he excels at something more than you, and probably he/she is right. Agree with him, and he/she will love you. (Remember what is said in the Ramban’s letter: “If you are wiser than he, remember that he is more righteous than you, for he sins by mistake while you sin knowingly…”)
3) Everyone is more interested in his own needs than in you; therefore, draw his attention to the point where your interests and his coincide.
4) Don’t try only to get a person to do something, but try to get him to want to do it, and to be happy doing it.
5) Guard against getting into bitter arguments with your friends, for this will distance and separate you from them.
6) Don’t talk about yourself so much. Talk with your friend about him, and he will be interested in hearing you. (Most people’s favorite word is “I,” and they find nothing more splendid than their own name.)
7) Listen to what others say, make an effort to remember their names and details about them, and they will love you.
8) Don’t criticize your friend openly; it will only make him more obstinate. Criminals, even the worst murderers, never admit their guild in their hearts.
9) When you speak with your friend, admit the truth, otherwise he will hate you - and rightly so.
10) Remember what the best doctors say, that important as it is to understand the illness, it is more important to understand the patient, because a large part of every illness, and sometimes the entire illness, comes from the patient’s state of mind. If you can correct this by showing him plenty of love and fellowship, the illness will pass.
One who follows these rules will eventually find it easy to rise above his instinctive reactions, because he has accustomed himself to look at things from his fellow man’s point of view.