Mistakes are a part of being human. Appreciate your mistakes for what they are: precious life lessons that can only be learned the hard way. Unless it's a fatal mistake, which, at least, others can learn from.
No one is ever really taught by another; each of us has to teach himself. The external teacher offers only the suggestion, which arouses the internal teacher, who helps us to understand things.
He who always thinks himself as weak will never become strong, but he who knows himself to be a lion, rushes out from the worlds meshes, as a lion from its cage.