We all know the main tenets of interviewing: practice ahead of time, arrive early, dress professionally, and bring copies of your resume. Most of us are also familiar with some major deal breakers at interviews, such as interrupting your interviewer and lying—but while many basic interview do’s and don’ts are common sense, there are plenty of less obvious behaviors that can reflect negatively on a candidate.

Everything you do in an interview lends the hiring manager some insight into your professional habits and abilities, from eye contact to body language to how you answer the toughest questions. To make sure you’re representing yourself in the best light, make sure you avoid these common interview habits that would make any interviewer question your professionalism:

1. Not following directions. Though this may seem obvious, not following directions can happen in seemingly insignificant (though still impactful) ways. For example: an interviewer should usually give you everything you need to get to the right location on time and find the right people. If you are asked to report to reception on the fourth floor of a building, it’s important to keep that information on hand; showing up on the sixth floor and having to be escorted to the correct one is one of many ways you can show a lack of listening skills and, as a result, unprofessionalism.
2. Answering “I don’t know” or not answering a question at all. Though it’s perfectly okay to be a bit stumped by a tough question, it’s never acceptable to let an interview question go unanswered. If you really have a hard time answering a question, take some time to think about it or, worst case scenario, ask if you can return to it later. The last thing you want to do is treat your interviewer’s inquiries as optional.
3. Exhibiting poor body language. Slouching, fidgeting, biting your nails, and other such displays of body language can communicate a lot to an interviewer. Slouching may make you seem disinterested or lazy; on the other hand, sitting at the edge of your seat can appear desperate. Fidgeting and biting your nails can betray feelings of anxiety and nervousness which, while normal, can be a problem—especially if they interfere with your interview performance.
4. Not doing your research. Though nobody expects a candidate to be an expert on the ins and outs of a company, it is expected that someone interviewing for a position has researched the employer they hope to work with. If you show up to an interview without any knowledge of the company, their mission, or their most recent developments, it could reflect very poorly on you as a professional; in addition, anyone interviewing without prior knowledge of the company can often miss out on great opportunities to learn more about the position.
5. Not asking questions. Unfortunately, many candidates still show up to interviews with the idea that they need to impress the hiring manager and not the other way around. Interviews are a two-way street, so it’s important to ask some questions of your own; not only will it help you learn more about the opportunity, it will show that you are looking for a job you’d be a great fit in, which is something that employers care a great deal about.