When I was younger, we looooved a show called Saved by the Bell. It was a cheesy, Saturday morning show that followed a bunch of students over the course of many years. One of the characters on the show was fixated on going to "Stansbury" and was pretty diligent about academics. At one point, she had trouble balancing school work and her after-school commitments (specifically, being in an all-girl pop group while taking geometry) and she resorted to taking *gasp* caffeine pills. This led to a "very special episode" and a truly epic scene in which her best friend discovered her secret.
You'd be surprised by how many choices I had when it came to this gif.
I told you it was cheesy. My point is that going to extremes to "look good" to colleges is not a new phenomenon, but with so many people taking a turn at being a college admission guru, I think more people are spending unnecessary time and energy strategizing when it comes to their activities.
My advice:
1. Get involved in some stuff you like.
When I was in school we were obsessed with the idea of the "well-rounded student." The only alternative was being nationally recognized in something, so we all aimed for well-rounded. The philosophy here has evolved. We're building a well-rounded class. In a well-rounded class, there's room for all types. Some students are going to be rounded and others are going to be pointy. It all makes the class interesting. Don't "over think" things. We're looking for students who are involved in some things that they find meaningful. There is no check list and no "ideal" activity list.
2. Don't apologize if your interests change.
I can't tell you how many times a student has expressed fear over dropping an activity that no longer fits into their busy schedule or isn't as rewarding as it once was. This is totally fine. Now, I'm not saying you get to check out on commitments you've made once you have a couple admission offers on the table. I'm saying that if your priorities change, that's okay.
3. Quality over quantity.
There are students with long lists and there are students with short lists. Everyone knows that student who manages to be everywhere. People wonder how they get things done, but they somehow figure it out. Everyone also knows that student who has a short list, but shows serious depth in one or two areas. Both of those students probably have some interesting, impressive things to share in the activity section of their application. Don't get bogged down in the number of things you can put in the Common App's activity chart. Put your activities in the chart and move on the next section. This part of the application should be easy to complete and make you feel pretty good about yourself, no matter how long your list is!
Oh, and if your list isn't long, don't feel pressured to throw filler in there.