In that all hypnosis is self-hypnosis, the hypnotic state originates from within the mind of the person being hypnotized.  The hypnotist is in essence a guide who directs and leads the person into the hypnotic state.  The hypnotist induces the hypnotic state by using certain words and phrases that the subconscious mind understands.  Various techniques like deep breathing, imagery, cadence and tone of voice are used as well.