On his website, John Holland (pictured) offers Weekly Intuition Tips(1). One of them deals with how to develop "clear seeing" or clairvoyance, where intuitive information is conveyed as images in the mind's eye. To get in touch with this ability he advises placing a candle in front of you and gazing into it for a few minutes. "Close your eyes and observe the afterimage. Let it fade, and do the exercise again to strengthen your third-eye area," he writes.

1. http://www.johnholland.com/press_media_recentarticles.asp