Mirroring, cross-matching, pacing: rapport skills
From NLP we know that certain behaviours will get noticed at an unconscious level, but possibly not at a conscious level: things like the speed someone is moving, the size of their gestures, rate of breathing, rhythm of speech...
Breathing is the most obvious one, but don't mirror it when they're talking. Rather, talk in sentence fragments in sync with their breathing. Test this one at least!
You can also match more psychological things like sensory preference - if they talk about feelings using phrases like "dragged out" or "weighed down", you can do the same. If they tell stories, so can you.
Normally we do this unconsciously and naturally, so if they look/sound natural then they won't get noticed.
This sends an unconscious message to them "You're like me in some way", although you get a slightly different kind of rapport depending on how you mirrored/matched them.
Mirroring/matching is a type of 'pacing'. Another type includes when you say things to reassure people like "you must have tried really hard" or "do you like chocolate?" ;)
Once you have rapport (how would you know?) then you start to lead or rather, they will start to follow you in some way.
Various trainers including Richard Bandler have mentioned that you can get rapport without pacing by being outrageous and/or dynamic in some way.