Any savvy high school student has known that he or she should take Advanced Placement or International Baccalaureate courses if he or she wants to be a competitive applicant to top universities. College admissions are definitely getting more and more competitive, but high school students are getting more and more strategic, even the ones who can't afford to go to the elite prep schools that are essentially breeding grounds for the Ivy League.
And while it's certainly in the student's interest to take as many Honors, Advanced Placement or International Baccalaureate courses as he or she can, it's also important to be reasonable. It's unlikely that any student can handle a full course load of AP courses, especially if he or she wants to participate in the extracurricular activities that admissions committees really like to see (oh and maybe see their friends and have some fun occasionally, too).
Students should think critically about their skill set when choosing which AP courses to take. It's rare to find someone who excels at every single subject to the degree that that he or she can score a 3 or higher on the Advanced Placement test for that subject. (And it must be really hard to like the people who are.) Students should think about what classes they've loved and succeeded in in the past. Does she love to read? Does she recite Othello quotes in her sleep? Then maybe the AP English Language course is a good one to take.
Students should consider both if they will get a strong grade in the course ("B" at the minimum, preferably an "A") and if they can earn a passing grade on the AP exams. Admissions committees look at the rigor of a student's course load (how many advanced courses they take, over how many different disciplines), the overall grade point average (top colleges are turning away truckloads of students with un-weighted 4.0 GPAs), and also if the student is taking an Advanced Placement or International Baccalaureate exams, and what scores the student is earning on those exams.
Admissions committees want to see that students are challenging themselves in their course load, but they also want to see that the students are succeeding in those more challenging courses. This is why it's not advantageous for a student to just take as many AP or IB courses as his or her school offers, unless he or she is truly certain of earning a high grade in the course. If the student doesn't know if he or she will earn a passing grade on the AP or IB exam, that's less of a deciding factor.
Taking the exam and not earning a passing score is not a deal-breaker for most colleges. A passing score is considered icing on the cake, and not-passing score is not a detractor. University admissions departments don't want to discourage students from attempting the AP Microeconomics test just because they're not sure if they'll earn a score of a 2 or 3. Students are rewarded for taking the challenging courseload, as well as the exam, and if they earn a high score, it's great, but if they don't, they shouldn't stress about it, at least as far as getting into college concerned.