What can I do with my extracurricular activities to get me into Stanford?

Your ideas are great and your extracurriculars are also looking good, your holding good positions in them. You just need to keep a good GPA throughout high school and do decent on ACT (about 27-31) and you should be able to get into Princeton. Also consider doing an athletic extracurricular activity. It will increase your chances of being accepted into Princeton. Same thing goes for Stanford University.