Here is a bit of a sample account on what to typically expect:
" The first couple visits were spent with him hypnotizing me to find out what the cause of my sleeplessness was. Well, of course, at first he had to see if I was susceptible to hypnosis because some people aren't. I was. Now it's been a while since I've been hypnotized, but I'll try to remember how it goes as best I can.
It starts with breathing, deep breaths in and out. Then you visualize/feel all the tension leaving from each part of your body, starting with your toes, working up to your head. Once you are totally relaxed, the counting begins. You sink deeper and deeper into yourself until the hypnotist reaches 10. Now I can't recall if I was encouraged to visualize or if I just naturally did because of my experience with meditation. But I would picture myself walking further and further into this forest. When the hypnotist reached 10, I would be at this house in a pool overlooking the ocean. (I'm a Cancer, I'm water obsessed). A lot of times my childhood cat Snuggle who died when I was 19 would be there, sitting by the pool hanging out with me. This was the safe place where my conscious mind would go while I was under hypnosis. I could hear my psychologist talking to me and feel myself responding to him, but mostly I was just chilling with my dead cat by the pool. I know. I'm a freak. Whatever.
Anyway, I remember that he would ask me to lift one arm and then the other and how weird it felt. And then he would ask me about memories of nights I couldn't sleep. I was not at all surprised when the first memories he uncovered as causes of my insomnia had to do with my abusive relationship. Then the next memory was of that night before 8th grade when my best friend moved away. Again, not so surprising. The shock came when I remembered the night before I started 3rd grade, right when we moved to Oak Park. Apparently I was unable to sleep a lot back then too largely because I feared I was going to be alone and friendless. Apparently the root of my sleep problems go all the way back then! It was weird because I barely remembered what my bedroom looked like at our first house in Oak Park, but I saw it crystal clear under hypnosis.
So once we got to the root of the problem, my psychologist taught me how to do self-hypnosis, in the hopes that I could teach myself to fall asleep in a hypnotized state. Self-hypnosis was basically the same as the hypnosis he did: the breathing, the relaxing of the body, the counting and walking through the forest to the pool...
And it worked quite well. Using self-hypnosis I was able to cut down my Ambien usage from an insane 30 mg/night to 5 mg/night. And honestly, if I hadn't been in a stressful life situation at that time (I was dating an alcoholic, it was not good), I bet could have cut the Ambien out completely."
Consider practicing before the more you know how it works/the processes you will be going throough, the better liklihood it will work for you.