Lucid Dreaming: A dream in which one is aware that one is dreaming. With the 'awareness', you can control it and "step in" your dream scenery and imagine yourself in there. And...you are there!!
Lay down and go to sleep. This works if you are extremely tired. Lay on your back with your arms to your side and your eyes closed. STAY PERFECTLY STILL. You must stay awake. Your brain will send signals to your body to see if you are asleep. These signals include: getting an itch, changing body positions, wanting to blink or mover your eyeballs around. (Remember your eyes should be closed) . YOU MUST IGNORE ALL THESE IMPULSES. After about 20-30 minutes you will feel a weight on your chest; you may even hear weird noises. You are now in sleep paralasis, if you open your eyes you will begin to hallucinate, and you will be able to move your body. Your body is now completely asleep. Now that your are aware that you are dreaming, you can shut your eyes and begin to dream instantly. You will be fully aware you are dreaming and can now (with some practice) control your dreams.