From The Sleep of Clear Light and The Dream of the Earth
There are four main foundational practices in dream yoga. Although they are traditionally called the Four Preparations, this does not mean that they are of lesser importance and are to followed by the “real” practice. They are preparatory in the sense that they are the foundations upon which success in the primary practice depends. Dream yoga is rooted in the way the mind is used during waking life, and it is this that the foundational practices address. How the mind is used determines the kinds of dreams that arise in sleep as well as the quality of waking life. Change the way you relate to the objects and people of waking life and you change the experience of dream. After all, the “you” that lives the dream of waking life is the same “you” that lives the dream of sleeping life. If you spend the day spaced out and caught up in the elaborations of the conceptual mind, you are likely to do the same in dream. And if you are more present when awake, you will also find that presence in dream.
From The Tibetan Yogas of Dream and Sleep by Tenzin Wangyal Rinpoche