Experience

As we successfully complete activities and goals, our confidence in our ability to complete the same or comparable things in the future grows.

Driving a car is a basic example of this. Most people who have been driving for a while do so almost instinctively; they don't have to think about which peddle to push or how to navigate a traffic junction; they just do it. In contrast, a trainee driver will most likely be frightened and will need to concentrate hard. The trainee lacks experience and, as a result, confidence in their driving skills.

Gaining experience and taking the initial step, on the other hand, might be quite challenging. The prospect of starting something new is frequently worse than actually doing it. This is where preparation, learning, and an optimistic attitude may help.

Break roles and tasks into tiny, attainable goals. Make sure that each of your goals meets the SMART criterion. Goals should be Specific, Measurable, Attainable, Realistic, and Timed.
Whatever you do, strive to be the best you can be. The better you get at anything, the more self-assured you become.