If you’ve never read Robert Cialdini’s Influence, you should run to a book store, buy it, and read it all immediately. Cialdini provides an excellent overview of persuasive principles that drive human behavior that are widely applicable to almost any situation. The principles of influence are:
Reciprocation: Doing a favor for someone often gets you a favor in return.
Commitment & Consistency: People hold an ideal of staying consistent with their behavior.
Social Proof: People look to others when they’re not sure how to act themselves.
Liking: People do business with others they know, like, and trust.
Authority: People defer to others in authority when making decisions.
Scarcity: People don’t like to miss out on something valuable and scarce