Strategy is a big part of acing any test. Doing practice drills, reviewing content and implementing best practices can help maximize your score. But even students who do all of that prep still make some completely avoidable mistakes on test day. Here are seven of the most common don'ts -- and how to avoid them.

If you're still putting together your test prep plan, take one of our free practice tests to see where you measure up. From there, you can find the best prep option for you.

Get Too Stressed

It's totally understandable for you to be nervous leading up to the ACT or SAT, but I urge you not to let those nerves get the best of you. Instead, have a relaxing night before the test and show up well rested. Breathe deeply at the testing center if you feel yourself freezing up – even during a section, it's worthwhile to take a 30-second breather rather than freeze up or start making avoidable errors —and just keep in mind that if things don't go the way you'd like, you can (almost) always retake the exam.

Forget Your Supplies

You may be prepared to mentally answer every question, but are you physically prepared? Unless you're taking an electronic test, you'll need a valid writing implement—usually a number two pencil—and should bring some spares, just in case something goes wrong. If you're allowed to use a calculator, make sure you've got fresh batteries in it. Snacks, if allowed, can help keep your energy levels up on longer tests, and a watch can help you stay on schedule. All of these are test day essentials you shouldn't leave home without!

Misunderstand the Test Format

The ACT and SAT are quite similar, but they each have their own nuances you'll want to know before the big day. Not only that, but each section can have slight variations in formatting — the number and type of questions can vary, just as the time you have to answer them can. You've probably spent a lot of time preparing for the test's content, so don't let yourself be thrown off by the test's structure or instructions. Use books like our ACT Prep and Cracking the SAT to become well-acquainted with the tests ahead of time.

Forget to Watch the Time

A key to performing well on either of these tests is sticking to a solid pace. And it's impossible to do that if you don't watch the time. Note that any watches used on test day aren't allowed to make any noise, nor can they connect to the internet, so leave those smart watches at home!

Spend Too Much (Or Too Little) Time on A Question

Some questions are harder than others. That does not, however, mean that they're worth more points than others. Don't waste your valuable time trying to score one point if there are other, easier questions that you can solve first. That said, don't underestimate a question's difficulty. The test makers know you're working for speed, and they'll try to trap you with an appealing (but wrong) choice. Make sure you slow down long enough to read every choice before committing to one.

Leave Questions Blank

Even if you can't figure out the answer to a question, you should never leave an ACT or SAT question blank. If you know a question would take too long to solve — or that you won't have time to come back to it — eliminate the obviously wrong choices, choose from the ones that are left, and keep going. Unless your test has a penalty for guessing — an extremely rare occurrence nowadays — you should never leave a question blank.

Doubt Yourself

If you finish a section with time left on the clock, by all means, double-check your work. And if you find an error, absolutely fix it — every point counts! But most of the time, the answer you choose initially is correct, and the changes students make actually lose them points. Only change an answer if you know why the option you originally chose was wrong.

If you're still putting together your test prep plan, take one of our free practice tests to see where you measure up. From there, you can find the best prep option for you.