h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

Sunglasses spring to mind at once. It is possible to mask all sorts of emotions by simply covering our eyes. Wearing clothes that do not accentuate body language is another way of control.

Good point. Sunglasses are in a class of their own. I think it's quite rude when people keep on their sunglasses while getting introduced or discussing anything serious.

You'll often see women - especially young women, for some reason, playing with dangly bits of their clothing. A good example is when a woman winds a necklace or the tie at the neck of her clothing round her fingers or even strokes it against her cheek or lips.

This is a dead give away. So, if you do this - don't! unless you want everyone to know that you're either attracted to the person near you or thinking about what you'll do to the person you left at home!