Avoid pursing the lips. This conveys either tension or an attempt to appear shrewd – either way it does not go down well.
Raise your eyebrows. This opens up the eyes and makes you look more open generally, whereas squinting makes us look slightly sinister. However, the elevation of the eyebrows needs to be relaxed and confident; excessive furrowing of the brow comes over as stormy and troubled.
Opening the palms conveys the message that you have nothing to hide and can therefore be trusted.
Avoid barrier signals such as folding your arms, clutching things to your chest, covering your face with your hands or blowing smoke in the other person’s face.
Mirror the posture and gestures of the person you are talking to. This will put them at ease because you are showing that you are ‘just like them’.
Know what you are going to say and deliver it with conviction and enthusiasm. Use an average tempo (neither a drawl nor a machine-gun) and minimise throat clearings, long empty pauses and repetitive phrases. Such things are distracting and reduce credibility.