There are many positions of authority in this world, from the small (supervisor at a tiny two-person company) to the huge (president, prime minister, or king of a large country), the personal (parenting) to the impersonal (CFO at a huge corporation), the petty to the influential, the abusive to the noble.
Part One: Take a sheet of paper and fill it with every position of authority you can think of. The more specific you can get the better (CFO of a particular company rather than ‘CFO of a company’), but try not to get stuck on variations of the same few types of position.
Part Two: Look through your list. Pick out a fictional character you’d like to write about, and choose for him an interesting and unlikely position of authority. What would it be like if he obtained this position? What would he try to accomplish? How would he affect the lives of those he has authority over? Write for at least ten minutes. If you don’t have a fictional character you’d like to use, then use yourself!