I tend to make my RC an all-day awareness sort of deal. There are certain things that tend to be constant for me in waking life (like body aches and feeling gravity) that generally don't transpire in my dreams. As I maintain awareness, I ask myself once in a while "What are the chances of this being a dream right now?"

My RC's serve as more of a purpose to prove why this isn't a dream, at this moment. I find that lately, I'll randomly ask myself this very question while dreaming, too