Interview people in leadership positions and ask them the lessons they learned from experience. You need to do a presentation on what you learned from the interviews.
Here are a list of questions you could ask (not limited to)
Do you think leadership develops with experience?
Are there one or two experiences you look back on as having been especially valuable in helping develop your own leadership? Please describe briefly.
Have your own views of leadership change over time?
Do you ever reflect, after the fact, about how effective your behavior was in a particular situation? Is this ever a source of new or different insights?
Is there any advice you would give people early in their careers about leadership?