5: It's not all about the academics
Ivy League colleges are, without a doubt, full of people who are just good at school. You'll get to know the type: even though they've lost years of their life writing 40-page papers and studying for 6-hour final exams, they want to keep going to school for 12 more years to get a Ph.D., and then they want to spend the rest of their career teaching and grading other students in school. These people certainly exist at Ivies, but they're the exception, not the rule.
Plenty of applicants have exemplified intelligence in different ways, either on a basketball court, or doing community service in Latin America, or running for office in student government. If you've excelled in something that you're passionate about, Ivy League schools will be content with the occasional B on your high school transcript. They want a large, diverse group of students—so don't try to be anyone but yourself.
Keep these tips in mind as you get to work on your applications, and who knows, maybe I'll see you visiting Columbia in the spring!