All hypnosis is self-hypnosis. The individual is always in control, not the 'hypnotist'.
The technique that I use is simple. I have the individual tell me in detail how they want a situation to be (stop smoking, lose weight, ride a subway, etc). What will success look like to them, what will they see, what will they hear people saying, what will it feel like, lots of multi-sensory details, in other words. Then I take them through a simple relaxation process. If the person can't relax or if they fall asleep, this doesn't work.
The goal of relaxation (an alpha, day-dreamy state) is to by-pass the critical beta or waking state of conscious. If one is awake and it is suggested that she wants to stop smoking, the waking brain says 'no'. When in the relaxed, but conscious alpha state, a suggestion, the individual's own suggestion, can be described and a picture of how the individual wants the situation to be is created. Even though the individual is ambivalent about change (I love smoking but it scares me), in the relaxed state, the suggestion has a better chance of changing that person's choices in the waking state.
When you see a stage hypnotist, (UConn would have James Mapes play to multiple sold out performances every fall back in the day) they 'test' their audience by suggesting, for example, that there is a balloon tied to one arm and a heavy object in the other. Then the hypnotist watches who did what he suggested. Those people have proven that they will choose to do what he tells them and he brings them up on stage for his act. Mapes was a stage genius who was also a clinical hypnotist helping patients deal with pain or prepare for procedures. In my training, filled with mostly MD's and nurses, we watched a stomach operation where the patient had been trained in self-hypnosis, and went through the operation with no anesthesia.
Most impressive.