Sometimes confidence is simply refusing to rehearse your weaknesses all day.

Confidence is often described as a feeling that arrives, when in practice it is closer to what you stop doing. Much of the ground you lose is lost to private rehearsal, running your shortcomings in a loop before anything has even happened. That habit does not prepare you. It just tires you out before the moment arrives.

Notice how much of your preparation is really pre-emptive self-criticism. Cap it. Give yourself one honest pass at what could go wrong, write down what you would actually do about it, and then stop returning to the subject. What is left over after the rehearsal ends usually looks a lot like confidence.