You seek extra curricular activities because you WANT to. Not because you think you're filling a square for an academy application. If you had NO extra curricular activities, I would say to find things that interest you, and get involved. Also, strive in your passion in those extra curricular activities to develop leadership positions in them. But you obviously have some extra curricular activities. That's good. And hopefully you are doing them because you like them. However, if you have interests, and you aren't involved in those interests (Extra Curricular activities), then you would then be considered to not have much motivation.
See, it doesn't matter what the extra curricular activities are. Some people believe that "Military Oriented" activities such as Civil Air Patrol, Junior ROTC, or Scouting somehow carries "More Weight" than say Choir, marching band, young republicans/democrats, or even the stamp club. Well, they don't. What matters is that you're involved with activities that include team building, leadership, and selfless acts of contribution. So, the question to you then is: Are there some additional extra curricular activities that you WANT to be involved in? If the answer is yes, then get involved in them. If the answer is no, then don't. The academy want you for who you really are. The reality is, if you're involved with a number of activities, and by "nature", you strive to excel in those activities and advance in their hierarchy, then a military academy most probably seems like an environment that you too might feel comfortable in and challenged. If you aren't motivated to do activities, excel in them, be highly involved in activities with other individuals, etc... then a military academy may not be the type of environment that you'd feel comfortable in either.
So my advice when it comes to what can you do, is: Be involved in whatever activities you WANT to be involved in. Excel in those activities because you want to. Be involved in volunteering in areas that you want to. Study hard, and get the highest GPA possible for you. (Don't look or ask what the "Standards" are.) Get the best you can. If you CAN be a 4.0gpa, then that is what you should be striving for. If the BEST you can do is 3.70, then that's the best you can do. Same with the SAT/ACT. Do the very best you can. Remember, the academies/military is made up of people who are continually striving to be the BEST they can be. If you are the best you can be in high school, then you should definitely be applying for the academies. Because that's the type of person they want. Best of luck to you. Mike.....