I hope you do well in your Junior year and do well on SAT or ACT. I would also advice you to maintain a high GPA and rank high at your school. UC offers a guarantee UC admission to the top 9%, so it’s important to make that top 9%. If you have time start writing essays on anything about you, your family, your surroundings, your ambition, your hobbies, etc. perfect those essays by making it serious yet fun. Select a meaningful community service now. Help at summer camps with special needs, volunteer at low income day camps like the Y and I mean not just a few hours, but a full dedication. For medical, volunteer at hospitals or medical research.
I can tell you that at my daughter’s school the 12 that were accepted at Berkeley all graduated cum laude, which at her school was 4.5 or higher. My daughter was waitlisted with perfect gpa 4.88, perfect Math score with leadership and lots of community service. Thankfully she got off the waitlist in the first round.
If you don’t get in, go through the transfer route and perform extremely well in CC with great recommendations.