I'm a former Princeton admissions officer. I did that job for two years from 2004-2006. During that time I read probably 2500 applications, spoke at about 80 high schools, and physically voted on whether or not to admit about 5,000 applicants.
I believe applying to elite schools is a total crapshoot unless you satisfy an instutional need of the university (minority, athlete, rich person, super elite academic/artist/entrepreneur). That said, it's incredibly important to make sure that there's nothing WRONG with your application before you send it off.
A good college application (like a good movie according to Siskel) has 2-3 good qualities and no bad ones.
That's where I can help.
Many applicants are deep-sixed simply because no one told them not to include X in their application. I suspect HNers would be a crowd that might have this problem.
In the spirit of this week's Offer HN spree, I will give 15-minute reviews to college applications from Hacker News members who reach out to me through my profile info.
I will not make edits or write anything on your app. I will look for red flags and inform you of any you find and my general impression of your strengths as an applicant.
Note: My experience is 100% in undergrad admissions. I have no experience with grad school applications and any advice I give on those must be taken with a grain of salt.