The principles of influence are based on the work of psychologist Robert Cialdini, who identified six universal factors that influence human behavior. They are reciprocity, scarcity, authority, consistency, liking, and social proof. You can use these principles to enhance your persuasive and influential customer communication by applying them in different ways. For example, you can use reciprocity by offering something of value to your customers, such as a free trial, a discount, or a gift, and then asking for something in return, such as a purchase, a referral, or a review. You can use scarcity by creating a sense of urgency or exclusivity for your product or service, such as a limited-time offer, a countdown timer, or a low stock alert. You can use authority by demonstrating your expertise, credentials, or endorsements, such as a certification, a testimonial, or a logo. You can use consistency by reminding your customers of their previous commitments, actions, or beliefs, and then asking them to act in accordance with them, such as a follow-up email, a reminder, or a confirmation. You can use liking by building rapport, trust, and affinity with your customers, such as using their name, showing empathy, or finding common ground. You can use social proof by showing your customers how other people have benefited from your product or service, such as a rating, a review, or a case study.