If you have been practicing the first two exercises till you can accomplish the minute times set in each exercise, you should be able to handle the following exercise with no problem.
I've included 3 levels of this exercise because some people find this exceptionally easy while others struggle with it. The only difference between the 3 versions is the distance between the two objects you will be concentrating with.
For all 3 versions, sit at a comfortable distance from the computer screen in a relaxed mannor. Then hold your finger approximately half way between the screen and your eyes. Using your field of vision as your guideline, align the tip of your finger just below and between the two images.
Your concentration should be on the tip of your finger. Allow the focus of your eyes to blur slightly and you will begin to see the two images move closer to each other in your field of vision. Your goal is to align the two images on top of each other so that you see an equal armed cross in the center and maintain that alignment for at least 1 minute, 5 minutes would be much better.
Once you have managed the minimum time on a regular basis, move on to the 2nd version of the exercise where the images are a little further apart and there fore a little harder. When you accomplish the 2nd version, move on to the 3rd. By the time you accomplish the 3rd version on a regular basis, you will be a pro at controling your concentration, if you have been honest with yourself and have practices the exercises instead of just thinking your 15 seconds is enough.
For version number 1

For version number 2

For version number 3

Learn Telekinesis - Concentration Exercises
1. Concentration Exercise #1
2. Concentration Exercise #2
3. Concentration Exercise #3
4. Concentration Exercise #4