In the past I've laid down for hours, unable to get any success.
Yesterday I tried again, only this time I stopped paying to myself, and let my thoughts drift, just kept bring up that I was going to try and lucid dream. After about 30-40 minutes I felt like everything was shaking and then heard a "whooshing" sound in my ears, but got too excited and it stopped.
How do you keep your heart rate down when you are getting close to SP?