How we change what others think, feel, believe and do
Encourage them to talk, then pay close attention, gazing directly at them. Look at their face and into their eyes as if you cannot drag your eyes away.
Match their emotions in this. If they are describing achievement, look pleased. If they are describing a hurt, look sympathetic.
Be careful with this. Do not stare -- use a soft and flattering gaze that says 'you are wonderful'. If they start to look at all uncomfortable, pull your eyes reluctantly away with an apologetic brief smile. Glance back frequently as if you are dying to gaze at them again.
If they seem happy with this, you can also turn body-on towards them. If they are less comfortable, look at their face more and eyes less, with occasional glancing away.
A politician, meeting a set of people greets each in turn, gazing softly and smiling directly at them. The politician asks a question and then listens attentively, holding their gaze.
Gazing directly at another person signals deep personal interest and is common in romantic situations. When done outside this scenario, it triggers the same response as you effectively 'romance' them. Although it may seem to be best cross-gender (heterosexually), it is also surprisingly effective in same-sex situations.
Staring directly at another person can also be an act of aggression, saying 'I am more powerful than you' and trying to make them look away first, which means you must be very careful if you are trying to create rapport! Particularly where the gaze is same-sex, it can be interpreted as within-gender rivalry. Two secrets for this: first, it is a lot to do with how you are thinking, and secondly you need to watch very carefully for signs of discomfort and respond immediately, as above.
An important note: Your eyes and the muscles around them signal much your emotions (they are the 'windows of the soul). So when you are looking interested or sympathetic, you must actually be interested or sympathetic.
And the big