There are many ways to do such, but I wanted to post one for now.
1. Set aside a special place, the atmosphere you build up will help still the mind.
2. Choose a time that is right for you. Dawn and dusk are the most popular.
3. Make sure to use this same time everyday to condition your body.
4. Get in a position that is comfortable for you, but you must have your spine and neck straight. Also, face North or East to gain the most out of this session.
5. Instruct your mind to quiet itself for about 20 minutes at first. You can add more time once you find out if this technique works for you.
6. Regulate your breathing. Slow, deep breath, then exhale and repeat.
7. Don't be afraid to let your mind wander, for if you forcefully try to blank it out more thought will wind up coming.
8. Now rest your mind on a focal point, usually the mind or torso which is filled with light.
That is the basic routine. After practicing for awhile you may find that you wake from a trance. That is exactly what you are aiming for. It is basically meditation, but this is a way to train your whole body (and the mind) to accept things like dreams and such much easier.