Take a look at the
Class of 2026 Class Profile. The numbers suggest you should be in the top 5% of SAT/ACT test-takers. Graduate in the top 5th of your HS class. Letter in one or more varsity sports (team captain should be your goal). Participate in extracurricular activities (that you legitimately enjoy) and seek out leadership roles. JROTC/Civil Air Patrol/Scouts are popular and teach leadership skills.
I suggest distance running as a sport (Cross Country) or incorporated into your training. Your CFA requires a 1-mile run after completing the other tasks (with limited rest in between). Running skills will pay dividends in the admissions process and at the Academy.
USAFA is 7,250 feet above sea level. Running at that altitude is very difficult and you will run frequently during BCT. You will also be expected to do the AFT (1.5-mile run) and PFT (600-yard run following physically exerting exercises) twice a year. If you fail to hit your AFT and PFT minimum scores, you are placed on RECONDO, a mandatory reconditioning program that eats into your limited free time.
Good luck!