How we change what others think, feel, believe and do
'Matching' is a kind of 'sloppy mirroring', still reflecting back non-verbal information, but doing so in less obvious ways.
When they display some form of body language or other non-verbal communication, synchronize your non-verbals with theirs, but without direct copying.
You can do more matching than mirroring, but again be careful about over-doing it. It should feel natural and empathetic. If it feels odd, then you might want to wonder why.
If they cross their legs, you could cross your arms. If they scratch, you could rub your arm a bit later. If they cough, you could make another sympathetic noise. If they frown, you can look pensive. If they talk fast, you could move fast.
Matching and all other forms of reflecting work to create rapport only when they register it subconsciously but not consciously. In this way, it triggers subconscious processes of liking without them realizing why.
It is less obvious than mirroring, which allows you to do more of it. However, as with all such methods, there is a limit, and more matching does not necessarily lead to more rapport.
Sparenberg and colleagues (2012) found that matching the other person's body part is the most important part rather than matching of movements when getting others to like you.
Matching, in some ways, is the non-verbal form of paraphrasing.
Sparenberg, P., Topolinski, S., Springer, A., and Prinz, W. (2012). Minimal mimicry: Mere effector matching induces preference. Brain and Cognition, 80 (3), 291-300