Try starting with some random nonsense phrase you repeat in you mind for a period with your eyes closed. This clears your immediate references. After a period, you'll drift into an alpha brain wave state where you can willfully enter into a state of lucid dreaming. I got into this via an interest in trancendal meditation (sp?) and continued into other meditation styles. These days, I find that I can use this to visualize scenarios in my software projects at a depth that is difficult to explain with words.