The easiest way to start this procedure is as a matter of first importance, disclose to yourself you want to dream of the most relevant past life in relation to your life at this time. Then, imagine yourself falling backward through time as you fall asleep. Focus on the sentiment of being elsewhere. As you do this, you can revisit your life, imagining that you're getting more youthful and more youthful. Then, return to birth. Imagine that you're going past your introduction to the world. Before long, you'll feel like you're falling into another time all together.
It may take some an opportunity to train your brain to do this, however, after a while, the past life dreams will come and you'll want to record them as soon as you wake up. You may already have dreams of a past life, or of several past lives. To differentiate, search for the signs plot above.