How to use non-verbal communication to build rapport?

It is not what you say, it is how you say it,” is a phrase that comes to mind when thinking about non-verbal communication. Voice quality, eye contact, facial expression, hand gestures and body position are all a part of how we convey non-verbal messages and are particularly important to consider when working with clients.

There are books on this, usually in the context of Sales. 

It completely depends on culture. For example, how we shake hands, has different meanings in different cultures. But generally you can refer to book "Human touch" fore more.

Smile 

Enthusiastic Tone 

Use appreciative gestures and hand movements 

Its about being true to yourself. If you are honest, supportive , caring and helpful. It sends positive signals

hi , 

     In non-verbal communication our gesture is very important, how we built eye contact, our body movement,time and space.

It's training and practice, one can learn from observing people who practice or able convey subtle messages to those around. A good grasp on personality types, can also help initially. There's lot of content on Web.