Here is an interesting article from Network World. Brian Brushwood describes four simple techniques that can be used to get people to do what you want: (1) confidence and control; (2) give something away; (3) use humor; (4) make a request and give a reason.
Mind Games: How Social Engineers Win Your Confidence
Social engineering and mind games expert Brian Brushwood has not come by his knowledge in the traditional manner of school or business training. Brushwood is the host of the Internet video series Scam School, a show he describes as dedicated to social engineering in the bar and on the street.
In addition to his passion for teaching people about social engineering cons, Brushwood is also a touring magician who frequently performs on college campuses and has appeared on the Tonight Show. He first became interested in social engineering years ago as a means to enhance his performance and pull off secret moves successfully. Brushwood said his understanding and use of the term social engineering goes beyond the security industry perception.