Choose a topic at random. At first, you should choose an easier topic to avoid (one that comes up, but does not occupy your thoughts for hours every day). You should go about your day trying to avoid thinking of this topic. Make note every time you think of this topic,as this is to be considered a break in focus. You might find that it helps to choose something you do not wish to do, such as exercise, and perhaps walk a block(when in a safe location) for each time that you have a break in focus. However, at the sign of exhaustion, you are instructed to stop practicing immediately.
At the end of each day, make notes in your journal about the topic you chose to avoid, your thoughts, and how many breaks in focus you have had.
Do not proceed to the next exercise until you have three or less breaks in focus at least three days in a row, or have practiced for more than a week(choose whichever comes later).