Just a quickie here. A psychic gave this tip recently and it has done wonders for me. If you find your mind is quite busy - consider writing an article, maybe for an imaginary newspaper, explaining what's going on in your mind and how it affects you and whether or not the thoughts are welcome. Allow the thoughts that are in the incubation stage to be expressed in your composition and try to come to a conclusion in your final paragraph.
I've managed to empty my head of all sorts of stuff this way and I find myself at peace afterwards. The thoughts become like pennies in your pocket and tend to be nicely tired out, like you'd want your kids to be before bedtime