There are things you can start doing as early as 9th or 10th grade to position you for any university as well as the service academies. One of the first things to do is meet with your school's college placement counselor about your plans and start working out your critical courses for the rest of your time in high school. One of the things you will find in these forums is a surprisingly large number of prospects who are having problems squeezing in all the math and science courses they really should take, especially if they intend to pursue a Bachelor of Science. For the service academies you really need to take the following courses: algebra II, geometry, trigonometry, pre-calculus, calculus, chemistry with lab, physics, and a very rigorous grammar course. It would be beneficial if your calculus, chemistry, and physics courses are AP and that you take the exams as they can help you validate courses at USNA. If you lay out your course of study early, you can squeeze in all of these courses without overloading.
I personally also strongly feel sophomores should start studying for and taking the SAT and/or ACT exams; my mantra is "familiarity breeds better scores." I know this is not endorsed by everyone, but pursuing an appointment to one of the service academies is very competitive, and it is my belief that an ACT score of 32 (for example) will be more impressive to the Admissions shop than a 26. Shoot me if I'm wrong, but that is my fervent belief.
Start searching for ECA's that are compatible with your personal interests and get involved with the objective of becoming an active, productive participant aspiring to leadership roles. It would be good to have a couple of organizations, be they affiliated with school, church, or community. Quality is more important than quantity here; don't overload to the point your academics are undermined - two or three will be adequate if you're being productive. Also look for opportunities to get into some of the leadership programs such as Boys State or Nation, Hugh O'Brien Youth, Eagle Scouts, Civil Air Patrol, Sea Cadets, Young Marines, JROTC, etc.
Finally, you should be involved in some athletic program! All of the service academies expect their cadets/midshipmen to be physically fit - and more!
You need to work on a balance of strength, endurance, and agility. Do some lifting, running, pull ups, push ups, crunches in addition to any organized sport.
Do go to the website(s) of your favored service academies and look for their visitation programs; eg, STEM, NASS, sports camps, etc. You really owe it to yourself to learn early rather that later what you are going to get yourself into if you get selected for an appointment. The Naval Academy's STEM programs are available to young people as early as the summer between their 7th and 8th grades and is a small, highly selective program. Applications for STEM will become available early in January at
www.usna.edu/Admissions. For those who are going to complete their junior year in 2014, the Naval Academy Summer Seminar program is likewise small (2250 participants) and very competitive. The application for NASS will open in mid-January also at
www.usna.edu/Admissions. Sports camps and some leadership programs are available through the CAMPS selection at
www.navysports.com. This may be a better course of action for varsity athletes as you will get to meet and work with some of the coaches. NAVY also have walk-in Admissions briefings available every day except Sunday in the Halsey Fieldhouse just inside Gate ! at the Naval Academy; check the schedule before you head to Annapolis.
So, there is plenty for any serious prospect to be doing as freshmen and sophomores and you may as well get started after this Christmas break. Best wishes to any of you who decide to pursue this course of action. The process is long, strenuous, competitive, and a great opportunity!