Last ACT attempt was the fall of my sophomore year. I’m hoping for marked improvement during the October test.
Keep hammering on your test prep. Definitely try the SAT if you haven’t. My daughter started with the SAT then took the ACT and had better success. Average ACT is 28/29 so you should be trying to get close to that before you consider submitting test scores.
Chemistry, physics are required. Pre calculus is the minimum requirement but Calc 1 is probably preferred. My daughter got in with PreCalc. College classes are looked upon favorably, so getting good grades in those will help.
Athletics are very important. Coaches can’t necessarily just get you in, but they will advocate for you. Each sports recruit is assigned a score of 0, 1 or 2. Basically it’s like 0 is good enough to be in the team, 1 will make a positive contribution to the team, and a 2 is a major game changer on the team. I’d say maybe lean toward whichever sport you think you’d contribute the most. I think it’s possible to be a 2 sport athlete, but it’s a demanding place and that may be a lot.
Like others have said, essays are important. Put a lot of thought into those. Read all the directions carefully and follow them! Use all the words but don’t go over. Get well educated people you trust to proof read. Grammar/spelling errors stick out like a sore thumb.
Also remember even if it says optional (essays, letters or rec), they’re not optional. So everything you can.
Apply for AIM in Feb. It’s a fairly realistic program and will give you a little taste. If you don’t like AIM, then CGA probably isn’t for you. My kid figured out real quick swab summer is much worse.

. They will evaluate you at AIM and that will be considered in your academy application. Also, you’ll do the PFE there and can use it for your application if you’re satisfied with it.
In whatever clubs/community organizations you’re active in, try to get into a leadership role. Or, at least take the initiative to spearhead some sort of event or activity that you can own and be able note on your resume or talk about if you get interviewed.
Best of luck!