I think that is a excellent idea about the light switch ! !

My reality check involves pressing my index finger into the palm of my hand
as I say to my self "is this a dream". So during the day I do this many times "watching around to make sure no one is watching of course". Then when I am dreaming my finger passes through my hand. "No Pain" LOL !

Not sure what to do if you can't find or unaware of your hands in a dream.

Another thing that I am starting to combine is looking at my watch more than once as the read out is usually different both times or looks strange.

Good Luck !