<p>Advice: Honesty. Really. Also caffeine. I wrote mine, since I was doing so at the end of junior year, on about a 1,000 hour sleep deficit (no joke). It ended up being very stream-of-consciousness (I did edit it into something approaching coherence, but as I was /editing/ on that thousand-hour sleep deficit, my editing was also lacking), but my counselor (somehow) went from:
Counselor in March: So, what’s your SAT score?
Self: 2360; 800-800-760.
CiM: What, YOU?!
to:
Counselor in June: OMG YOU ARE SO IMPRESSIVE THIS IS GREAT
Self (thinking): …How did my ramblings about physics (example quote: I do not believe in the limits of the possible, because that would be depressing. How sad the universe would be if we could never travel faster than the speed of light! I mean, what would we do if we were stuck on Earth for eternity? That would be sad.) convince you I was smart? You totally didn’t like me before this.
CiJ: Like wow!
Honesty! And give lots of examples about everything. Counselor letters are much improved if instead of going “Lirazel loves to learn about all sorts of different topics” they can say “Lirazel loves to learn about all sorts of different topics. Although probably a history or classics major, she borrowed a friend’s AP Physics textbook so that she could read the chapter on quantum mechanics, because she wanted to know more than her own textbook told her.”
Err on the side of giving too many stories rather than not sufficiently enlightening your character, but your counselor probably has a lot of these to read.
Oh, and for 5, ask your friends for suggestions.</p>