This is a very helpful exercise and it's very simple and easy to do. It relaxes the mind and helps develop an open awareness of what is coming and going in mind, without having any particular interest in any of it. And it’s just a matter of watching your breath.
Over time, this simple exercise strengthens your capacity to move and focus attention on objects in consciousness at will, which will make it easier for you to look at yourself. It also reveals certain characteristics of human consciousness.
Do it for about 10 minutes at a time. Set an alarm clock so you'll know when the time is over.
All that is required concerning posture is that you sit comfortably enough to be able to remain seated for 10 minutes in a row. There is no need to pay any particular attention to posture. Just sit comfortably. Your eyes can be open or closed.
We use the breath in this exercise because breath is something that happens on its own, and doesn't require your conscious attention to continue.
Just sit quietly and begin paying attention to your breath, as it goes in and out of your body. Make no attempt or effort to control or monitor the way the breath is happening; just watch the sensation of the breath as it passes across the nostrils, on its way into and out of the body. The sensation is cool as it passes across the nostrils coming into the body and warm on its way out of the body. It is that feeling, that sensation at your nostrils that you will pay attention to and focus on.
Try to create a tight focus on the sensation of the breath coming into the nose and out of the nose. With every out breath, you will count mentally: 1, 2, 3 ... The first out breath is 1; the second out breath is 2, and so forth. You will count up to 10.
Should it happen that during the counting you find that your attention has been distracted and you’re paying attention to something other than the sensation of your breath – a physical sensation, a train of thought, a sound, or something crossing your field of vision – simply say to yourself silently, inwardly: Distracted. Then move your attention back to the breath and start counting again from 1. If you get to 10, start over again from 1.
Do this for 10 minutes, once a day. In the beginning, you will probably not be able to count beyond 2 or 3. Don't be discouraged. Keep trying, don't give up. Even if you stop at 2 or 3 and start over every time, the work is being done. In time, this will improve your capacity to focus your attention.
The point here is not to get to 10; the point is to develop and strengthen your capacity to focus your attention at will, as you would lift weights or do push-ups to develop and strengthen your muscles.
You can follow John's instructions and look at yourself right now. See how here: