Well, who gets into H/S??? People who
1. Have always been amongst the best - so you get a disproportionate amount of people who are valedictorians, with super good awards, etc. etc. This applies to both academic and professional lives
2. The well-connected and wealthy - People don't like to admit this, but this helps... I mean if you come into the school with your dad running a huge family business, well then... If you were a pro sport player, a famous TV personality, etc. this also helps
3. The amazingly dedicated - You see a lot of go-getter types here. People who have already spent five years teaching in Africa, or developing their own startup
4. The successful - Do you already have two startups in your name? Have you already led huge projects with lots of people? registered three patents? written a book? etc. etc.
These are not the only types who get in, but lots of folk come from one of the types above...