Warning - long post.
Do not dedicate the entire four years of high school to increasing the chance that you will be admitted to a “prestigious” college.
College is a way to prepare for the rest of your life. If you spend your entire high school doing stuff because they may increase your chances at a “good college” you are not only missing out on the many wonderful and enjoyable things that you could be doing, you are also missing the chance to help yourself prepare for the 40+ years that you will work and the 60+ years that you will live after you graduate from college.
Moreover, focussing on “college acceptance” even ignores the fact that acceptance to a college is only the very first step for the four years in college.
What you should be doing is deciding what classes to take in high school. Figure out whether you have interest in particular direction (life sciences, engineering, history, art, etc), and choose classes in that direction. If you don’t yet, take a wider set of classes. Your counselor and student handbook will help you with that.
The point of your studies is to provide you with a strong basis in general knowledge and skills, as well as the foundations for the acquiring further skills and knowledge during college or whatever track you choose. For students who are on a college track, the classes are not to help a student be accepted to a college. They are to provide the foundations for the courses that they will take in whatever college they end up attending.
The purpose in taking the most rigorous classes is not because “colleges like this”, it is to build studying habits and skills. That is why a student should take the most rigorous classes that can deal with, rather than the most difficult classes that the school offers. The colleges which prefer students who took the most rigorous classes that their high school offered are not accepting these students as a “prize”. They are colleges whose own courses are extremely rigorous, and they need to know that students have the ability to do well in such classes.
As for extracurricular activities.
You should not really be looking at ECs from the point of view of “what are the colleges looking for in my extra-curricular activities”. Your main focus on ECs should be what YOU want to achieve from your ECs. You find martial arts enjoyable and helpful in your life - go and do martial arts. You care about the homeless? Go and volunteer in a homeless shelter. You enjoy learning advanced math or science, and then competing with others on these topics? Do that, and do it well.
Your ECs are for you, not for college AOs.
My advice is, therefore: choose classes based on your interests, make sure that they are as rigorous as will allow you to succeed in those classes, and engage in extra curriculars that interest you and help you now. I promise you that, in the spring of your junior year, you will be able to figure out which colleges are the best for YOU. Which colleges will help you achieve what you want to achieve in life. Maybe not the most prestigious colleges that you can imagine, but colleges which with help you succeed in college and in the rest of your life.