8. Talk in Terms of the Other Person's Interests

It means finding common ground with the person you're talking to and showing that you understand their point of view. When you talk about things that the other person is interested in, they're more likely to be engaged in the conversation and to feel like you're on their side.

Obviously, we’re all interested in talking about what interests us — and this engagement promotes liking. 

For example, when women were more engaged in a conversation on a first date, they were much more likely to report being attracted to the guy.

This is the most important principle in Carnegie's book. It's about taking the time to learn about other people's interests and concerns. When you show genuine interest in someone, they're more likely to feel like you're paying attention to them and that you value their company.