When I am teaching, I will often sit with my back to the park so that everyone who is listening to me is also looking at things that move and grow. This is not a distraction from my point: it is a way to suggest that the point of what I teach is for people to move and grow.
One of the things that people hope to grow through my training is confidence. Confidence is not something you grow from a seed: it does not start out small and gradually increase in size and complexity the way a tree does. Confidence is a side-effect. To grow it, you have to create the right conditions. The seeds you use are not confidence seeds: they are usually seeds that look and feel entirely different than the confidence they eventually generate.
For instance, a seed of courage will often produce some confidence eventually. While you are nurturing courage, you feel the opposite of confident. You might feel shaky, scared, anxious or afraid. If things were easy, you would not need courage. Courage appears when you face fear and keep going. And after the moment is passed, courage will often leave confidence in its wake.
Another seed that leads to courage is called will power. Will power is not sexy and attractive and confident. Will power is the determination to do something hard, or to do something repeatedly. We all have a limited supply of will power, and the only way to grow more is to use up what we have. When we go through the false starts and the missteps and the backsliding and make will power stick, we often find that confidence has shown up, too.
You will also find confidence growing in the aftermath of the kind of caring that leaps up and takes action because something has to be done and you are the person with the best shot at doing something to help someone in need. This is not caring about: caring about is often something that happens in our heads or hearts but does not change us very much. This is caring for, taking action to make something better for someone else. It often involves inconvenience and uncertainty and giving up something you would rather be doing. The reward it leaves on your pillow the next morning is a tiny grain of confidence.
Perhaps there is a way to grow confidence with same progress and certainty that turns a maple key into a tall maple tree. But I think it is more likely that confidence grows from paying attention to what we know to be true in ourselves and in the world. I think confidence is a side effect that grows after you do the right thing.