To develop your clairvoyance, you must be able to attain a higher level of consciousness. You need to work on your spirituality and this can be done in several ways. The most common way is through tapping the power of your third eye. Another effective way is through constant meditation.
The purpose of Zazen Meditation is to free your mind of the materialistic hold our lives have on us and once you are able to allow your thoughts to enter and quietly leave without investigation you will no longer be limited. This will provide you the quiet calm needed to see the truth of your nature and your place within yourself and the world. Your body, mind, and breath will become one.