I think it would be the art of listening. It covers about everything: If you listen to your children, you'll know what makes them happy. If you listen attentively in school, you will learn and grow in your abilities, until you've achieved a Ph.D., then you'll have the best job possible. If you listen to the news and to history, you'll learn how not to make the same mistakes. If you listen to your constituents, you'll know what to promise them. If you listen to medical and health professionals, you'll be as healthy as your environment will permit. If you listen to your spiritual leader, and listen to all who seem to have good ideas and histories, your spiritual senses will increase, and you will find peace. Listening to people and making them feel like you've truly listened will help them to like you. Thus, you'll become more influential. Listening is almost a panacea to all problems and pursuits.