Make sure first that there are no external distractions such as telephones or people who are likely to interrupt you. Sit on a chair, but don't lean back. Keep the spine erect. Doing so will help you to stay alert. Alternatively, choose your own favorite position for meditation.  

Then become aware of the entire inner energy field of the body. Don't think about it - feel it. By doing this, you reclaim consciousness from the mind. If you find it helpful, use the "light" visualization I just described.

When you can feel the inner body clearly as a single field of energy, let go, if possible, of any visual image and focus exclusively on the feeling. If you can, also drop any mental image you may still have of the physical body. All that is left then is an all-encompassing sense of presence or "beingness," and the inner body is felt to be without a boundary.
Then take your attention even more deeply into that feeling. Become one with it. Merge with the energy field, so that there is no longer a perceived duality of the observer and the observed, of you and your body. The distinction between inner and outer also dissolves now, so there is no inner body anymore. By going deeply into the body, you have transcended the body.  

Stay in this realm of pure Being for as long as feels comfortable; then become aware again of the physical body, your breathing and physical senses, and open your eyes. Look at your surroundings for a few minutes in a meditative way - that is, without labeling them mentally - and continue to feel the inner body as you do so.  

From Practicing The Power of Now, Eckhart Tolle, pg 61.