First impressions are formed within seconds of meeting and—accurate or not—opinions are formed and perceptions take shape. College is a critical time to make good impressions, particularly on professors, who are the ones giving grades, writing letters of recommendation, and assisting with a student’s journey toward graduation.

College students often overlook the messages their actions and behaviors send. And at large universities, it’s easy to view oneself as just a number in a sea of students. But guess what? Teachers are more perceptive than they seem. During my 10 years of teaching higher education, I have been able to solidify a list of what does—and doesn't—help students go a long way in the eyes of a professor.

Many college students are hyper-focused on what to do in class, but end up disregarding common, simple and easy things not to do. Want to make a good impression and not end up on your teacher’s “naughty list?" Read on for nine straightforward tips.

1. Don’t be late

Logical, right? You’d be surprised how many students saunter into class late without the slightest explanation or apology. Not only is this inconsiderate to the professor, but it can be quite distracting to the rest of the class. Instead, plan to arrive at least five minutes early. Getting to class before it actually starts is a great way to interact with the faculty member one-on-one.

2. Don’t be mute

It’s easy to get swallowed up by the more outgoing, extroverted students in the class. But sitting throughout the entire semester without saying a word can have a negative effect on your overall grade in the course. Most professors include participation as part of the class grade, and while it may seem insignificant, student engagement is highly regarded by teachers.

3. Don’t come unprepared

Benjamin Franklin once said, “By failing to prepare, you are preparing to fail." Let that sink in for a minute. Not only does being unprepared look bad, but it adds to anxiety and nerves in the classroom. Make sure you’ve read the text and have everything finished that’s due—the earlier the better.

4. Don’t be overly casual

Some professors prefer students to address them by their first name, while others are strict about using their formal titles. Even in departments where communication is familiar and on the casual side, you never want to cross the etiquette line. Be careful about using slang or nonchalant language. When in doubt, err on the side of formality both in person and over e-mail.

5. Don’t send angry emails

Speaking of email, the marvel of digital communication has many upsides, but it can also come back to bite you if misused. As most students’ primary means of communication with faculty, don’t be tempted to send an email in the face of anger over a disappointing grade. Always let feelings subside—take a night to sleep on it—before hitting send on a questionable email to a professor. Better yet, schedule a time to talk to your professor in person. Remember, bad impressions are hard to reverse.

6. Don’t give in to distractions

Whether you’re in a physical classroom or taking your course online, distractions are everywhere. Repeat after me: Turn your phone off (or at least on silent). Additionally, put your phone away, in your bag, in the other room at home, so you’re not tempted to check messages or browse social media during a lecture. Again, give respect, get respect. Plus, you’re bound to miss important information if you’re looking at your phone or the TV.

7. Don’t take naps

The ultimate no-no: sleeping during class. I get it, being a college student means you function on little sleep and a lot of caffeine. But nodding off in class is plain old rude. Not only will you surely upset your professor, but you run the risk of missing the lecture, assignment directives, and critical class announcements.

8. Don’t leave early

As frowned upon as showing up late, leaving or logging out early from class sends a negative message as well. Many professors save important information for the end of class so you should always wait until you’re officially dismissed. Packing up early also comes across as disrespectful. When there’s emergencies or reasons known in advance for an early exit, communicate that with your professor in advance.

9. Don’t make assumptions

Not sure about what’s required for a project? Have a question about the upcoming exam? Always ask. Making assumptions or guesses about course work means that you have a 50-50 (at best) chance of being right. Why not just reach out to your professor with a polite email to clarify? Not only does that show that you’re proactive, but that you care about your personal success in the class. College is hard enough. Don’t let these pitfalls drag down your overall experience. Remember: think twice about what impact something will have on the impression you’re sending.

Jennifer Craven has taught at the college level for the past 10 years. She is currently an instructor at Mercyhurst University in Erie, PA. In addition to teaching, she is a freelance writer, specializing in parenting, lifestyle, and fashion industries.

Questions or feedback? Email editor@noodle.com