Looking good to college admission officers can seem like a puzzle with too many pieces to track. You've got things like GPA, extracurriculars and sometimes even work or volunteer experience to worry about. Then you'll have your application essays and potential college interviews — the list goes on and on.

Some elements of your application hold more weight than others, though, and a good number of schools in our book The Best 385 Colleges state that a very important factor considered during admissions decisions is “rigor of secondary school record." That rigor can be expressed in a variety of ways, so here are a few tips to ensure you stand out.

Tip 1: Take AP/IB Courses

Many students choose to boost their high school transcripts by stacking their schedules with AP (Advanced Placement) or IB (International Baccalaureate) courses — and that's a great way to do it! Essentially, these classes allow you to take college-level courses while you're still in high school. Moreover, many schools offer a plentiful variety of advanced subjects to take, from math to foreign languages.

However, since many of these courses require prerequisites, I recommend that you plan far ahead. You don't want to be left out in the cold your junior or senior year because you didn't take a required course while you were a first-year or sophomore. You also might want to stagger out your schedule. If you can handle a lot of AP/IB courses at once, great! That said, why overload yourself with difficult courses if you don't have to?

Tip 2: Focus on Grade Trends

Simply having a difficult course on your transcript is admirable, but the grade you earn is just as important. It's good to demonstrate a willingness to challenge yourself; it's also good to know your limits, and to not take on a class that you know will be too difficult.

That said, a bad grade or even a bad semester isn't the end of the road. Schools aren't just looking at a single point: They're looking at a collective whole, at how your grades have been trending. In short, they want to see a marked improvement over time. If you think you might not be quite ready to tackle an AP course, taking another step forward and excelling in that class can help alleviate any blemishes that might have come before.

Tip 3: Avoid Too Many Laid-Back Electives

To get your grades up, it can be tempting to take a step back and choose classes in which you know you'd excel. However, I implore you not to pick a schedule full of easy A's. There's nothing wrong with taking a few fun, laid-back electives, especially if the subjects are interesting to you; this is a good way to avoid getting burned out during the school year. However, a college admissions officer will notice if your schedule has too many. A positive grade trend or high GPA won't fool your prospective colleges. As we've been discussing, they want to see a certain -- well -- rigor when they look at your high school record.

If you're enrolled in AP courses, The Princeton Review can help ensure that you make the most of them with our cram courses and tutoring. Plus, our admissions counseling can help ensure you're on the right track to become a great candidate at your dream school. If you're not sure where that might be, it's never too early to start researching with books like our The Complete Book of Colleges and The Best 385 Colleges to start crafting your list.