Mark Coleman, a meditation teacher and the author of Awake in the Wild, offers this simple meditation as an introduction to mindfulness, or the state of nonreactive, receptive awareness that forms the heart of vipassana meditation.
Sit comfortably in an upright but relaxed position. Close your eyes and bring your attention to your nostrils.
As you breathe notice the subtle sensation of cool air passing into, and warm air passing out of, your nose. Without manipulating the breath, simply notice the sensation. Maintain your attention to every breath. Staying relaxed and mentally alert, become curious about each passing one as if it were your first.
If your attention wanders, simply notice the distraction and patiently return to the sensation of the breath. Your ability to stay present deepens by consistently returning to the current moment.
Do this exercise 10 minutes once or twice a day, gradually extending your sessions to 20 or 30 minutes each.