As for me, self-confidence comes over the years, since it takes time for a person to accumulate practice and be able to do something with confidence. If you take a random person and constantly tell him to change this will not happen and this person no matter how much if he has no experience, it is almost impossible. Experience brings confidence when you know a certain situation and know exactly what to do. It seems that instead of being afraid of something, you need to practice even if mistakes are made in the beginning. So do not give up and do not fight errors and unknown situations. You don’t even feel like you started to feel more confident.