It's definitely not too late! :) This is actually great timing.
Colleges like to see a strong academic record as well as a student who is well-rounded. Challenge yourself academically - whether that's AP classes, a community college class, or an academic extracurricular like debate or math club. As for extracurriculars, something like a summer job/volunteer work could definitely fit this category, as well as any extracurriculars you do during the school year, like sports or theater or the school newspaper. Community service is definitely a great way to learn a lot of skills, bolster your application, and make an impact on the world at the same time.
The reason that colleges like these things is because they want someone who is driven to succeed and passionate about what he or she does. Show passion in what you do - don't just join an extra club because you think it will help; do it because you want to. You will perform better and be happier that way.
You will also be able to showcase your passion and the personal side of yourself in the application essay and in any interviews, when senior year rolls around.