Meditation ranges anywhere from simple thought, to prayer, to power meditation. In meditation the person is usually reflecting or thinking about something. Or, the goal could be to reach a deep state of mind so as to communicate with spirit, deities, etc. However, a common meditation is to simply BE. This means that your brain is idle, your heartbeat is steady, and you are completely still, in all literal and metaphorical manners.
With that out of the way, meditation is either going to be really easy or really hard. Many people with A.D.D or A.D.H.D find it hard to meditate. Meditation poses are usually laying down or sitting. You know the stereotypical meditating where the person yoga-sits and chants "ohhhhhhmmmm"? Yeah, that's not necessary. Once you are comfortable in one of the positions, comes the hard part: clearing your mind. This can be incredibly hard for someone who has a hyper-active brain. Let's test:
DON'T THINK ABOUT ELEPHANTS!!
Let me guess, you thought of an elephant?
The idea that you shouldn't think caused you to do the opposite, because of how our brains function. To counteract this, focus on a clean image. A candle flame, ocean, swaying tree, or perhaps a flower? These quiet images help to create a calm mental environment for you to begin meditation. Focus on your breathing and visualize the air entering and leaving your body. Be aware of all your involuntary bodily functions; listen to your steady heartbeat.
But this us just to enter a meditative state. Once you're there, it up to you to decide where you'd like to go! Will you attempt projection? Or perhaps you want to build an astral home. Do you want to talk to your great-aunt Rosemary who still hangs around your home? Or maybe you'd just like to enjoy the stillness of your own mind.