Activities & Extracurricular's needed to get into Stanford (or any university)

Hello! I am currently a sophomore in high school and interested in getting into Stanford University. I'm planning on taking biology and or chemistry so that I can become a cardiovascular surgeon. I have already applied for internships at Children's Hospital and Denver Health, I'm just waiting on them to email me back. I currently have a 4.0 unweighted GPA, and have taken 2 community college courses as well as a couple honors classes. I have done and been in multiple extracurricular's/programs such as ambassador, Leaders Among Leaders, junior honor society, basketball, soccer, track, swimming, etc. And I'm in the process of creating a fundraiser for this summer that helps disadvantaged kids and families in my school and community. But no matter what I do, I feel like I'm not doing enough to convince Stanford admissions officers that I belong on their campus. It is my dream to get accepted to Stanford University, but I'm wondering what I should do (if I'm not doing enough) to get in.