The only thing scarier than a job interview is walking into a job interview unprepared.

Yet this is exactly what many candidates do. Sometimes, nervous interviewees don’t prepare because they’re trying not to think about the upcoming meeting. Super confident candidates skip prep time because they’re relying on their charm—without considering that another applicant may upstage them.

Regardless of the reason, lack of preparation can damage your chances by making you seem unprofessional or uncaring. To help you put your best foot forward, Company Folders has put together the 21 top tips for acing your next interview. Here’s a taste of what you’ll learn:

Before the interview

The night before your interview, organize all your supplies. This includes packing a pen and paper to take notes, as well as giving your portfolio a once-over so you can easily locate specific samples. You may also want to pick out your clothes in advance to reduce the stress of getting ready the morning of your interview.

Packing beforehand sounds simple, but it’s amazing how many candidates skip this step. Then they waste precious time looking for items they want to bring or trying on every piece of clothing they own. Preparing the night before lowers your stress levels, helps you sleep better, and makes it easier to arrive at the interview site on time.

During the interview

90% of what we say comes from our body language and tone of voice, rather than spoken words. Be sure that your body language is open and powerful—sit up straight and keep your limbs unfolded to show confidence. Maintain a friendly, professional tone by enunciating your words and speaking in an audible (not overbearing) voice.

One more thing to remember: interviewers like to throw out trick questions. If they ask a question you’re not sure how to answer, request some time to think about it. This shows that you’ll be a thoughtful employee—rather than making rash decisions. And it keeps the interviewer from sitting in awkward silence, wondering if you’ve suddenly gone deaf.

After the interview

The interview doesn’t end when you leave the building. Be sure to send a thank-you note within 1-3 days. This follow-up lets them know you’re still interested in the position. You’ll also want to send any additional samples of your work in a timely fashion, so the interview team can make decisions at their convenience.

Read on to learn more great trips for succeeding in your next job interview.