How to win friends and influence people by Dale Carnegie is a timeless classic.

It has so many beautiful words of wisdom that it's hard to apply all of them, but these 2 always tops my list

1. Remember that the people you are talking to are a hundred times more interested in themselves and their wants and problems than they are in you and your problems

2. There is only one way under high heaven to get anybody to do anything. Did you ever stop to think of that? Yes, just one way. And that is by making the other person want to do it. Remember, there is no other way