There are three categories of leadership competencies. Technical competencies make you good at the work your team does. Knowledge competencies make you good at figuring things out and fitting the work into the bigger picture. Ethical competencies make you a trustworthy person. The Army calls this approach to personal growth Be-Know-Do.
I think the most critical area of competency for leaders is ethical, for a very simple reason: if your team doesn’t trust you, they won’t follow no matter how much you know or can do.
Some leaders are very successful even though they can’t do any of the things their team does. No leader is ever successful over time if the team thinks he or she lacks character.
I use the Be-Know-Do framework for personal development, but these days most of my goals are Be goals. I’ve found that by focusing on being a better person, my leadership grows too. And I become the kind of person who naturally grows in knowledge and technical competence too, just by being diligent about what matters to the team.