The first few times that you use self-hypnosis, it is best to find a place where you can be undisturbed for a while. Sit or lie down, eliminate any distractions, and relax. This puts you in the best possible conditions for using the technique - however as you get more practice you will find that you can use self-hypnosis almost anywhere. Obviously it should not be used when you need to be alert - eg. when driving or operating machinery, etc.
The first step is to relax yourself: close your eyes, and try using imagery of waves of relaxation running down your body from your scalp downwards, washing out stress. Let the waves run in time with your breathing, first washing down over your head, then your neck, then your torso, then arms, and finally your legs. Feel the muscles in your body relaxing as the waves of relaxation wash over them.
Alternative techniques can involve fixing your eyes on a spot on the wall, or riding down in a lift/elevator from the top of a tall building, slowly dropping down into relaxation and drowsiness. The method you choose to induce hypnosis is up to you.
The next step is to use suggestion to deepen the state. This is as simple as saying to yourself something like 'I am feeling relaxed and comfortable. With every breath I am becoming more relaxed and more comfortable.'
Once you are completely relaxed and focused on your own suggestions, you are in a useful state of self-hypnosis. One suggestion you can usefully embed is that when you repeat a particular trigger word to yourself you will relax into this state.
What do you think that can this technique help to reduce the stress?