In today's' society in order to have an edge when networking, pitching, getting your ideas across or getting you own way, you need to analyze your target. That is the people you want to influence. You have to understand why they behave in the way they do, what are their weak and strong areas. Then take what you have observed and use it to your advantage. To start with, you must always have a goal as you analyze your potential target.
To be able to manipulate your target, you can use human psychology, body language, personality types,NLP and persuasion.