The principle of Liking
When someone likes you, they are more easily influenced by you.
The principle of Authority
People are more easily influenced by those they perceive to be an expert.
The principle of Scarcity
People value things they think are scarce.
The principle of Consistency
People have a strong desire to be consistent with their previous opinions, assertions and actions.
The principle of Reciprocity
People feel the need to pay back in kind. This goes for the material and the emotional.
The principle of Social Proof
People prefer to do what others are doing (crowd behavior).