One thing that stuck with me from the Scholar's Day FF presentation D & I attended was that they're "looking for kids who have developed a plan for their future and have already begun acting on that plan." They "realize students tend to change plans during college, but that if a student is able to develop and begin implementing one good plan, the next one, two, or five plans will be even better." (quoted loosely
So, I'd suggest taking an inventory of your skills, interests, and current involvement. Develop a plan - i.e. tie together these elements in a way that demonstrates a focus in whatever you may
want to study and become in the future. Practice articulating your vision through speaking and even interviewing if you have the chance. Many EC competitions provide this opportunity. Focus on service beyond showing up and collecting volunteer hours - develop service projects - strategize how to get others involved, expanding service opportunities for volunteers and benefits to those being served.
Read, read, read. It will expand your horizons and vocabulary!
This, at least, is what worked for my D. Good luck to you.