Reddit reviews Introducing Neurolinguistic Programming (NLP): A Practical Guide

In all honesty mate, my best advice would be to learn about the techniques used in social engineering. This can span from NLP, building rapport, covert hypnosis and micro expressions and much, much more.

I started on this book ages ago and it was a great introduction to this whole world.

After you have an understanding of how body language and words effect peoples behaviour, then you can move on to more advanced techniques.

This guy has a great YouTube channel with so many videos about NLP and hypnosis. If you browse a few of them just to get a real, physical idea of how people use language, and what words can be emphasised for a specific purpose.

In terms of other books, Kevin Mitnick has a few good ones about his life (google him if you don't know who he is). And also a guy called Kevin Dutton wrote a book called Flipnosis - The art of split second persuasion

The other thing I would say, and I can't really stress this enough, is try to observe your own and others behaviour and understand why and how people say what they say and do what they do. I like to do this by sitting in a relatively busy cafe and simply observing what goes on and how people interact.

Hope this helps.