Phantasy

What J247 described is the classic way for meditating. In my case, I have a mind that races and jumps, so the only thing that worked was to "signal jam" by flooding it with fast repetition. Because I'm religious, I recite meditative memorized prayers, but you can use anything - recite verses of a song, catch phrases, the Fibonacci sequence.

J247's is great, try it. But if it doesn't work, keep trying other things until you get what you need.