Ask yourself what you want to do in ten years. Public knowledge is that it takes ten years to become an expert.
Do something that builds those skills that are required in that field.
In the past you said that you want to become a leader
Solo activity's that could help you with that part are:
1) Start a blog.
Put complex thoughts into writing. It's an important skill to develop.
2) Read good books. Either fiction or nonfiction. It helps you to think abstractly.
Useful group activitys would be something were you can learn public speaking.
Maybe a debating club? A theater play? A toastmasters club?
It's not the talent that deterimens whether you will become a good leader but the amount of time that you invest in developing skills.
If you don't excercise on a regular basis I would also look into taking up a sport (dancing would also work) to excercise your body.
At least that are the suggestions that I would give a youger me at your age
