I'm working on the sequel to my first novel (not yet published) and in it I have a character named Phoenix Sheldon, a detective who is an expert at reading people. This guy helps solves cases because he is better than average at picking up on the tiniest clues (often non-verbal) that most people miss and weaving together the story of who the suspect is, or anyone he meets for that matter.
While researching for this character I looked up information on how to detect if someone is lying. It was actually fun gathering this info and I plan on using some of these methods of observation for use in my real life. Illusionists and supposed psychics use these small clues and devices in their work. Here's the link http://www.blifaloo.com/info/lies.php/.