But how to be lucid in waking? I don't think that knowing that you are in reality and not dreaming is enough... My though is that the key could be in lucid vivid memories from episodic memory.
What occurs to me: gamma brain waves, which (if I'm not mistaken) are often experienced only during lucid dreaming and transcendent states of meditation. The only way we normally experience this is by being aware of our state during a dream, so to have this same experience during waking . . . I don't know. It would be something quite profound, I imagine.