Anyone who can successfully read people can communicate and hold power. It's human nature to make decisions quickly, based on subconscious impressions of how a person looks and acts. Police officers and poker players often look for non-verbal cues in the people they deal with. They call these cues "tells" - and pride themselves on seeing "tells" where ordinary people don't. Here are practical tips for understanding the inner motivations of others, and for controlling your own message to the world.