I've had a few clients recently who, by coincidence, have had a similar issue regarding their self-confidence. They strive to beat those niggling self-doubts that creep into interactions with people whose opinion they might not even rate, but they still find themselves trying to prove themselves. Or they have a judgemental sound-track going on during the entire conversation - they hate it but they can't stop it.
So, I made a little animated video to summarise how we work together to coach those negative self-doubts away. It's not perfect as it's my first attempt and I can't believe how long it took to make a 3.5 minute clip - serious kudos to people who do this for a living!