1. It's most likely a lie. I am not saying that to start a flame war, I just have actual experience with this. As in years of dedicated experience.

2. Keep a dream journal.

3. Do reality checking throughout the day.

4. Meditate before sleep. Do a relaxation exercise. There's 100s of them.

"Lucid Dreaming: A Concise Guide to Awakening in Your Dreams and in Your Life" is the definitive book on the topic that everyone copies. No one has additional information.