Self-belief and hard work will always earn you success.
In order to do well, you must believe in yourself. No one ever got to the top by thinking they were terrible at everything. Confidence in yourself and your abilities are a must. If you don’t believe in yourself, who will?
Even if things don’t go as well as you would like the first time around, believe that you can do better the next time, and let your effort reflect your self-belief.