Rapport is the unconscious connection we have with other people. When we have rapport it is easier to communicate (even to disagree), understand them and help to influence or create a stable relationship.
Neurologically, we get connected to others through what we see, hear and feel. Neuro Transmitters known as mirror-neurons start to identify when someone is similar to us; therefore, in NLP we use this to an advantage.
By matching and mirroring another person (or many people) you can purposefully trigger the mirror-neurons of someone else as you become like them for just a few moments. In simple terms, the unconscious mind of the person you are communicating with sees or hears the similar behaviours or traits and fires of a neurological signal telling the body/mind “ah, this person is like me. I like people who are like me!”
A few things you can match and mirror are body movements like the crossing of legs and arms, tilt of the head, a lean in or back, where the body weight is centred, volume, pitch and speed of the voice, key words, experiences and concepts. Now, there are tips and tricks to building subtle rapport – if you overdo it you’ll get caught, and if you underdo it, it won’t be effective.