On Reddit, a wonderful thread where redditors detail their favorite "mind tricks." Here's a smattering:
When I walk through large crowds of people, to avoid walking into anyone, I simply stare at my destination. I look no one in the eyes. People actually will watch your eyes and they avoid the direction you are going. If I look into people's eyes as we are walking into each other, we are sure to collide. You have to let people know where you intend to go with your eyes. It always works for me, try it! (Poo_Smudge)
I'm a paramedic. When a patient is possibly faking unconsciousness we have 2 tricks to determine if they're really unconscious or not. First, you can lightly brush their eyelashes with your finger. Their eyes will flutter if they're faking it. Alternatively, if they're on their back you can lift their arm over their face and let it go. A conscious person will drop their arm away from their face. (Monkeybrigade)
If you're trying to find something, try looking right to left as opposed to left to right. Your eyes tend to skim over things if you search in the direction you are used to reading in, so skim the opposite way. It takes me a bit more effort to do this, but I notice more details. (icameintoadarkroom)
If you ask a question, and receive only a partial answer, respond with polite silence. Simply wait. A more complete answer will usually follow. (Kromulent)
I write books. My latest is a YA science fiction novel called Homeland (it's the sequel to Little Brother). More books: Rapture of the Nerds (a novel, with Charlie Stross); With a Little Help (short stories); and The Great Big Beautiful Tomorrow (novella and nonfic). I speak all over the place and I tweet and tumble, too.