This could include private rehearsal in front of a mirror, or role playing with a friend, or both. Then plan how you will manifest these behaviors in your day to day life. Take it in small steps to maximize your odds for success. Somewhere, some people get the funny idea that basking in success is being self centered or big headed. If you succeed, relish in it.
Fear is a funny thing.
Here so strong one moment that you cannot even imagine yourself living through the feared event.