If you are a technician (somebody who does a discreet function in an organization) and you accept a promotion to a leadership role, it doesn’t mean you remain a technician with a sprinkling of people stuff. It means you become the people person who also has to do a sprinkling of technician work. That concept is what I see most new leaders miss. The promotion is essentially a whole new role. Leadership development requires the same level of rigor that it took to be  a great technician. Book learning, mentoring, self-assessment, experimentation, group learning, and time. It is a whole new thing. Treat it accordingly.