There are three different levels of communication:

1. Intra-personal Communication, 
2. One-way Communication & 
3. Non-verbal communication. 

Among all these most important is non-verbal communication. The scientists have estimated that 70% of our communication is non-verbal and ironically most of us don’t know the effective ways of non-verbal communication. 

There are three major ways how we communicate non-verbally:

1. Eye Contact: We communicate a lot of emotion through our eyes. Eye to eye contact is very important in communication. Lack of eye contact can indicate that the person is hiding something, telling lies, avoiding the communicator etc. It may signal negative self image of the person.

2. Postures: Sitting postures or position also communicate a person’s attitude. Rigid posture may indicate stress. Folding of hands may indicate ‘not ready to open up’. Leaning towards to the communicator may indicate aggressive attitude or interested also. 

3. Gestures: Facial expressions, voice qualities & tempo, body movements, smile, head nods etc, are coming under gestures. 

I have a list of representative gestures and the meanings it ascribes to them, which I got from my counseling books. Those are as follows:

Erect Head: Self-esteem, Confidence, and Courage
Bowed Head: Humility, Guilt, and Submission
Touching Nose: Fear, Stage fright
Artificial Cough: Doubt, Surprise
Whistling: Genuine Self-Confidence
  
Non-verbal Communication is important and we need to learn the effective ways of non-verbal communication to be successful in this world. The above detail gives a brief & rough idea of what non-verbal communication is and how to go about it. If we observe people we are talking to we can learn more. I feel observation is the best way of learning effective non-verbal communication. 

All the best!