IMO a good RC should be super fast to perform, with a generally unambiguous result, and available to do wherever you are, based on nothing external to yourself: so that means, for example, nose pinch and hand check. Nose pinch gets the vote for best possible RC because you can also do it in the dark.

I only usually have vague notions of lighting: most often, bright daylight, dim twilight, vague indoor lighting. If I'm aware enough to check for a light source to see if I'm dreaming then I'm basically already lucid .