To enhance your leadership skills, I recommend you to be active in your school clubs or any other groups you could join. As you know, the definition is the action of leading a group of people or an organization. In other words, you could experience the direct/indirect leadership from any group activities rather than individual activity. Do not afraid to join the clubs and be proactive!
In my case, I was the president of student council when I was in highschool. I was responsible for selection of committee chairpersons and it helped me to think about HR allocation. In addition, I was also responsible to lead the school events and meetings which let me learn how to plan and operate the event from the starting point. There are lots of other lessons I learned from it.
As I said above, do not afraid to do something new and try it first. Especially, if you could take any role in your group, it would let you grow up in diverse ways!