The key would be to focus on a few things and stay with them. Progression to a leadership role is also key. Better to do a few things and do them well than doing lots of different things without focus and committment
Well, looking at the stats, the following seem to be well thought of "extracurriculars" by the academy: Boys/girls State, CAP (civil air patrol), public speaking, sports (obviously and with leadership position being key), some volunteer type activities. But I've only seen stats on Boys State, the others are guesses based on seeing who has gotten in and what extras they posted on various forums. But, you should really not worry about which ones, as long as you're into what you're doing, as has been noted.
OK Kiddo... you seem lost.
What grade are you going into?? Look at your school and see what kinds of clubs there are that interest you.... if you are into history/government then join Model UN or Mock Trial, if you are into science then join the science club. Run for class officer, student council etc... get/keep your grades up so you can qualify for NHS.... all of these usually do some volunteer work in conjunction with the club duties....get the picture??
If you are really into astronomy and your school doesn't have one then create one!!! Your volunteer work can come out of the club...i.e. teach elem kids about astronomy or tutor middle school kids in science.... just a random example.
Strive for a leadership role.... check and see if there is a Civil Air Patrol unit near you.... join it. I hear this is very big w/ USAFA.
Once you start doing then start progressing toward leading by being an officer.
The point is to do what you like and be passionate about it. If you are in athletics work hard and strive for team captain.
Don't worry about the number of clubs you join... aim for quality vs quantity.
Do not do car washes for the sake of doing car washes......
Get up and get moving and good luck!!!
I agree with all the above, especially to do things you enjoy. CAP has been really good for my family in general and my daughter in particular. Depending on how good your local unit is, you can get a lot of leadership experience and also good contacts with active duty and retired Air Force personnel. A lot of what CAP does is a mini recreation of the Air Force, including uniforms, command structure and customs and courtesy. It looks good in an interview if you have at least some idea of what you're getting yourself into.