Rapport

Rapport is a close and harmonious relationship in which the people or groups concerned understand each other's feelings or ideas and communicate well.

The word stems from the old French verb rapporter which means literally to carry something back; and, in the sense of how people relate to each other means that what one person sends out the other sends back. For example, they may realize that they share similar values, beliefs, knowledge, or behaviors around politics, music or sports.

There are a number of techniques that are supposed to be beneficial in building rapport such as: matching your body language (i.e., posture, gesture, etc.); maintaining eye contact; and matching breathing rhythm.

A classic if unusual example of rapport can be found in the book Uncommon Therapy by Jay Haley, about the psychotherapeutic intervention techniques of Milton Erickson. Erickson developed the ability to enter the world view of his patients and, from that vantage point (having established rapport), he was able to make extremely effective interventions (to help his patients overcome life problems). Some psychiatrists and psychoanalysts argue that without establishing a proper rapport the sessions don't have the same beneficial effects on the patients, as they won't be as open and communicative.

Building rapport is one of the most fundamental sales techniques. In sales, rapport is used to build relationships with others quickly and to gain their trust and confidence. It is a very powerful tool that veteran salespeople naturally employ, which allows them to close more deals with less effort.

Mirroring means getting into rhythm with the person on as many levels as possible.

Giving gifts or doing favors without directly asking for something in return can trigger feelings of obligation, but can be good when developing clients.

Commonality is the technique of deliberately finding something in common with a person or a customer in order to build a sense of camaraderie and trust. This is done through shared interests, dislikes, and situations.

...
Wikipedia