what to do to increase chances for american unviersites>?

hey there! i just wamted to ask of anyone can give me advice as to doing anything now so that i can increase my chances to get accepted into american ivy league universities? my gcses werent awful (i was ill and had been bullied) and im in year 12 but some issues had begun (medically) so now im taking time off and restarting y12 in sep this year, but despites my cicumstances i still want to use my time and do some things that can help me in the future...any help? thank you!!

True for the top 10 but not top 20. Vandy/CM/ND/etc all take a lot of test optionals, especially from countries where act/sat isn't widely available. It's more important that you've excelled in your home country's equivalent exams.
You need to be focused on outstanding extracurriculars, as the majority of American students shooting for an ivy are going to have published research, national/international awards or leadership positions, and prestigious internships. That will get you in the door for consideration but then your essays are what will set you apart, so make sure those are spectacular too and show what a compelling candidate you are.