With conversational hypnosis you can hypnotize people secretly, and without them knowing. But in order to do that you need to be able to read people.

Now what do I mean by reading people? I mean you have to be able to look at them, and interpret their nonverbal signals clearly so that you can understand what is going on with them, without them having to explicitly articulate it.

You do it by reading their body language, by watching their physiology change. There are people who can control their own body language, and they can fake it. But you can't affect physiology. Because physiology is controlled by your subconscious. And if you learn to read both body language and physiology and you will also see if there is a disconnect, and people are trying to cheat you. That is about as close to becoming a human lie detector as you can get.

You can watch people's pollster, you can watch their eyes, their pupil relation, the frequency in which they blink, and breathing patterns, changes in the tone of their skin color, eye movements, and many other indicators.

In fact, when you know to really observe the signs, you will be able to pick up on clues that other people completely miss. It happens to me all the time that people think I have psychic abilities. The funny thing is, when I tell them the truth, and tell them that I can see it because I watch their body's signals, they don't believe me. They don't believe that it's possible to watch so precisely that you can pick up so many details. They will rather believe in supernatural powers, which I find little bit sad. Because people aren't just making full use of what they got.