While you're in bed, clear your thoughts. Look up at the ceiling, and imagine it being completely black.. see it like a TV screen. What it is that you wish, imagine it *on your ceiling*, and hold this thought as you go to sleep.
This was taught to me by my dad at age 5. I kept pestering him to get me a kitty cat. Finally, he came up with this, thinking he was shutting me up. I tried it, imagining every detail of the cat that I wanted.
Imagine his surprise when the cat showed up at the bottom of the stairs the next day. We had her for 21 years - best cat I ever had