One of the best ways to keep someone interested in your story is to lead with something unexpected. This is not an example of that:
"The marching band practices every day after school for two hours. It's very arduous, but necessary if we want to perfect our formations."
Nobody would be surprised to learn that. But if you said,
"A polyester band uniform actually doubles in weight when it's wet. Every time we practice in the rain, I gain 10 pounds for the next two hours."
Now you've got my attention.
When you share something people didn't know yet, it makes them want to know more. It's like an intellectual itch they need to scratch. That's what being interesting means–people want to hear and learn more from you.
Of course, there's an art to recognizing what people might be interested to know about and how much they can take. If you drone on for twenty minutes about how to get to the expert levels in your favorite video game, a non-gamer is going to lose interest. But if you told me about life as a game tester, when you're paid to do nothing but play video games 8-hours a day, I'd be intrigued because that's something I could never imagine doing.
So when you're writing your college essays, doing a college interview, or even just having a conversation with someone you've just met, get them interested by sharing something they probably wouldn't have guessed. Give them the unexpected part of the story.