The importance of the four preparations to the later stages of dream yoga cannot be overstated. They are much more powerful than they appear to be. Furthermore, they are practices anyone can do. They are more psychologically oriented than many practices and will present no difficulty for the practitioner.
Simply doing a practice before going to bed may be ineffective, but with consistent practice of the preparations during the day it becomes it becomes much easier to attain lucidity in dream and to then go on to the further practices. Using these practices makes everything that happens a cause for the return to presence, and this will bring great benefit to daily life as well as lead to success in dream yoga.
If you do not have immediate results, even if you must practice for a long time before achieving lucidity in dream, there is no need to be discouraged. Do not think that it is useless and that you cannot accomplish the practice. Think about the differences in how you thought and acted when you were ten years old, relative to now–there is constant change.
Do not allow yourself to get stuck, believing that whatever limits you have in your practice today will continue in the future. Knowing that nothing remains the same, you need not believe that the way things manifest now are the way they must continue.
Experiencing the vivid, luminous, dream-like qualities of life allows your experience to grow more spacious, lighter, and clearer. When lucidity is developed in dream and in waking, there is much greater freedom to shape life positively, and to finally give up preferences and dualisms altogether and remain in non-dual presence.