Choose something that is very inconsequential to your life. That is, make sure you are very uninterested in the topic. So, if you are very interested in videogames, don’t choose that. A good example here might be deciding to focus on the nature of something in your room. Think about the thing you chose in your room or otherwise. Do this for 5 minutes in a sitting position with your eyes closed. If you are having a lot of difficulty staying focused, it helps to try to be mindful of yourself and your conscious state.
Breaks in focus include thinking abouthinking about the object, thinking about other things (such as your day), or not being mindful of yourself(an example of this is suddenly realizing after a minute that your thoughts drifted).
Note the amount of breaks you had and all other relevant conditions in your journal. When you have mastered doing this exercise for 5 minutes with 4 or less breaks a few days in a row, increase the time you do this exercise to 10 minutes.
When you can do this exercise for 15 minutes with 6 or less breaks in focus, you should continue to the next exercise.
This is a vital technique in being able to do psi. For example, if you are doing telekinesis, it helps to be able to think of one thing(such as the object moving) without any distractions. This cannot be overemphasized.