Yale requires 3 SAT 2 subject tests, so don't skimp on breadth of course. Most prestigious colleges want you to take math through Calculus (and if you're already past that, then 3 years anyway), four years of English, three to four years of a foreign language (usually four), three to four years of history, and 3 years of science.. So as a frosh you should try to take a science (usually Bio, sometimes Chemistry), English, History, a foreign language, a math class, and then if you still have space in your schedule, something fun. The point is to challenge yourself; take the hardest courses you can handle.