A start. As of now I haven't had the time to fully design this program, but the idea is to gather the best videos (or CD's) that would impart related information and provide "models" for "being cool".
To gain enough expertise
As with anything you want to be good about, you'll need to give yourself time to learn and to practice and to write and digest. And don't stop until you're as good as you want to be. If you write a mini-book of 30 pages on what to do, you'll find the investment to be worth it in terms of learning.
WHAT TO DO
Engage a partner or use a coach. So you're using the principle of champions: do something, see what you did, correct and improve it, frequently.
Practice in front of a mirror.
Look at yourself. Note the expressions that look good. Practice looking attentive (you've seen it, but we seldom have observed ourselves doing it.
Use mental reheasal
Mental rehearsal is a way of conscious learning, as you're careful to pay attention to the details. And actually rehearsing in front of a mirror plus recording yourself and observing what is happening. (Or record others and then observe what they are doing.)
For at least 30 days or however long you want to be intense at this until you get as good as you want to be, write down what you've observed. Who was cool, and why, what did they say, what about their mannerisms, were they caring, warm, what about their voice, tone.
What would you do differently?
Characters on TV that you admire:
Record the programs. Observe what they do, how they move. Practice it in front of a mirror. practice it on a recorder.
See YouTube: Enter Social Conversations:
Just some examples, that could be improved upon if someone would go through and screen a bunch of these:
CD Programs on social skills
Find some CDs on the subject.
OF COURSE, PRACTICE
If you do not practice, you'll not really install the level of certainty and expertise that you would want.
HAVE YOUR MATERIALS READY
Chit-chatting and winging it requires some extra skill and maneuvering in the moment. But, if you'll notice, people who are good at social conversations actually have quite a few routines and stories. Jokes or amusing stories can be good fillers, but they are mostly for appropriate parties or cardplaying or such.
Have a series of questions about them, but make it casual and easy rather than a quizzing process. Share your reactions about their answers and follow the lead of the subject.
Have 10 stories (written out) about your life, especially ones that are touching and/or relate to the other person.
Write out and keep 10 jokes available.