Successful hypnosis depends on a variety of things, but probably the single most important among them is rapport.  To support a good relationship between hypnotist and subject, wide rapport must be established.  Rapport isn't something that happens exclusively in hypnosis; every time you come into conversational contact with someone, rapport is established on some level.  The type of rapport you develop with subjects is the key to conducting successful conversational hypnosis.

Rapport is strengthened any time a person around you experiences a trance.  They will inevitably connect with you and your mind.  This creates a deeper sense of trust between subject and hypnotists, which allows for more successful hypnosis.

If you've ever met someone you have a hard time connecting with, rapport is responsible.  You may find yourself having the same conversations multiple times because of a sense of distrust and an inability to be comfortable with each other.  This shuts down thoughts and ideas, both subconscious and conscious, and eliminates any chance of successful hypnosis.

This is why it is so important to establish good rapport from the start by tuning in to the subject's interests and finding topics you can connect over.  Tell stories, share experiences, and be very sure to listen.  Only by acutely paying attention to what your subject says and getting a feel for their personality can you establish good rapport.

If you take the initial steps necessary to establish good rapport, all your hypnosis attempts will be more successful.  Hypnosis is not something that can be launched into; this usually results in failure, or the hypnotist just looking foolish.  Work on rapport first and foremost, and you will not find your subjects turning away from you.  Rather, they will be more receptive to you and more likely to enter a trance.