Self confidence is the first requisite to great undertakings.
Confidence takes a prudent risk. Confidence launches out in belief. A self confident person is more likely to find a way to do anything that's difficult than a person who wavers in self doubt and uncertainty.
The single greatest cause of unfulfilled potential in our world is inaction. Self confidence takes action and makes things happen. And if Arisotle was right to think that we all learn by doing, then it's the self confident person who is most likely to learn by being willing to try.
An old adage has it that anything worth doing is worth doing badly. I've always loved that. It just means that anything worthwhile should at least be attempted, even if we’re guaranteed not to be as good at it the first time as we’d like to be. The self confident person doesn’t worry about that or let the chance of initial failure scare him off from attempting something that needs to be done. And self confidence attracts others to our cause, making it even more likely that we will in fact succeed.
Of course, as Aristotle also taught us, for every virtue, there is a too-much, as well as a too-little. Confidence shouldn't replace competence or command in any situation. It should remain tethered to the real world. But the thing about confidence is that it can contribute to creating new realities, as well as working with those we already have.
Try an internal audit. Are you as confident as you should be to accomplish what you want to do? If not, then build your confidence first by building further competence, and then command over the relevant skills, or reviewing what you already have, and then give yourself that regular inner cheerleading that we all need for success in challenging enterprises. The philosopher William James once said that every champion needs precursive faith, an inner attitude of faith that runs ahead of the available evidence. Begin to enjoy a little more of it today. Confidently.