It's about lifting your consciousness out of your body which isn't so far off lucid dreaming. You don't have to be a lucid dreamer to do it. In fact, the way I learned to start was by recalling a vivid dream fragment - the kind of vividness just before you wake up - in which you're using your limbs (say, climbing over a fence or going through a gate) the idea being that it's easier to detach your astral limbs from your physical ones, and get going.

I had long imagined a temple of sorts, the entrance a drape which, once I was free of my body, I could pass through. But I've ventured about a bit. If you find visualising fairly easy you should have no trouble. You may have to experiment with different times of the day.

Good luck!