Elite University Students?

To make yourself competitive talk to your guidance counselor and parents early about your intentions. Take the hardest classes you can be successful in, plan on taking an SAT/ACT prep course to do your best on standardized tests. Pick the activities you excel at, so if you are a talented athlete go with that, if you are more interested/passionate about an activity go with that. The key is to also have some back ups, there are lots of other schools that are prestigious beyond Harvard or Yale. Try to be yourself and let your talents/interests show through.