improving my resume

That depends on what kind of college you wish to attend. If you are aiming to attend a Top20 college, you will need to show more course rigor and take either AP classes or IB curriculum. Most successful admits have either a full IB diploma or have taken between 8-12 APs. And that is typically in addition to taking DE classes or outside college courses. Top schools like Stanford and Harvard, want to see evidence of intellectual vitality. That may include writing supervised research papers, taking advanced coursework that is not offered by your high school, and getting unpaid internships with professors who teach in the field you are interested in applying to as a major.

Having top grades and test scores is strictly a threshold benchmark for application readers. They expect all their admits to have great GPAs and high ACT or SAT test scores. That itself doesn't make you unique or especially competitive against the 10s of thousands of other applicants with similar credentials.

Therefore you must also have intellectual vitality, amazing EC, and show signs of leadership and personal character which sets you apart from the fray.

Good luck