Principle of reciprocation. We are taught from childhood not to take without giving in return. When someone thanks you for service above and beyond the call of duty, rather than undermining your powerful position, implement the rule of exchange. Respond, “I’m glad to help. I know you’d do the same for me.”
Principle of scarcity. People want more of what they can have less of. Before you ever try to influence people, tell them that what you’re offering is unique. When you describe the uncommon features of what you offer, tell them what they stand to gain by working with you, and what they stand to lose if they don’t. People are more mobilized to action by the idea of losing something than they are by gaining that very same thing.
Principle of authority. Before you try to persuade someone, share your level of expertise. Have someone you know call the person and tell them about you. When do you ask that person to make the call for you? In the moment after “thank you.”