Engaging senses to distract you from your 'real body senses' is the main idea, in the longest lucid I've had I inspected things around me in great detail and the dream took on astonishing clarity/realism/stability, it really was like waking life. The only unstable dreams I've had were where I wasn't quite conscious enough to take the decision to inspect my surroundings, I hand-rubbed by instinct but that was only effective the first two times.