10 of the biggest mistakes interns make—and how to avoid them

Danni Zhou, Intern
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For interns, it can be hard to put ourselves out there. Sometimes we'd much rather hang in the background. What we don't realize is that's not a good strategy — for us or for the company.

Currently, I'm a student at the University of Pittsburgh and, this summer, an intern for CNBC Make It. But the summer after my freshman year, I interned for a local newspaper company in my hometown of Birmingham, Ala. I was incredibly shy. I stayed at my desk the entire day, spoke only when I was spoken to and hesitated to ask for advice about assignments.

I was afraid that the editors and writers were too busy, and I didn't want to intrude on their hectic schedules. Additionally, I didn't want to bring up "stupid" questions and look incompetent.

In hindsight, I hurt myself tremendously. At times I was told to revise stories or reschedule interviews, which could have been avoided if I had simply talked to my supervisors. I prevented myself from becoming a better reporter.

Now, I've learned that asking questions is an important part of internships.

"Too often interns will think they have to do everything by themselves — you don't! Your managers and teammates are there to help you overcome roadblocks and manage tough questions and issues," Sara Sparhawk, recruiting manager at Amazon, tells CNBC Make It.

"Interns should always be open to learning new things and not be afraid to go out of their comfort zones," says Steffie Eduarte, manager of diversity and campus recruitment at The New York Times.

Here are 10 more actions experts say to avoid.

1. Taking your internship for granted

Too many interns don't take the work seriously, Ilona Jurkiewicz, head of early careers at Thomson Reuters, tells CNBC Make It. Instead, they need to "really consider how their actions and behaviors are going to impact them short and long term," she says. Even at internships, performance and reputation matter and "can be a gating factor to their future success."

2. Repeatedly missing work

"If you're continuously late, calling in sick, or missing deadlines, that's going to be a red flag to your supervisor," says Lauren Berger, CEO and founder of Intern Queen, Inc. "If you're procrastinating or not coming in, you're impeding on the company's progress and missing out on the opportunity of the internship."

3. Dressing unprofessionally

"Interns should always keep in mind that first impressions can be really important," says Eduarte. So it's important to follow things like dress code. "You're not only representing your personal brand but the company on a daily basis."

4. Sitting at your desk all day

"An internship isn't just about the work, it's also about seeing if you like working at a company, and if it's a good fit. It's important to meet new people and learn about the business. Reach out to people for coffee or lunch. Make time to get to know your colleagues," advises Sparhawk.

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5. Pretending you're not burned out

"There are industries and roles where the workload is very high and demanding. Interns burn out and become exhausted, and they have a choice to make on whether this industry or company is the right place for them in the future," says Jurkiewicz. "The intern is really learning what gets done and most importantly how."

6. Mixing work with your personal life

"When you come in for work, do not consistently talk about aspects of your personal life. That can come off as extremely unprofessional and that you're not taking the job seriously," says Berger. "If the company hires interns in the end, you could jeopardize your chances."

7. Not paying attention to process

Figure out how your managers and co-workers prefer to do business and communicate. "For example, do they prefer short emails? Phone calls? In person updates? Adjust your style to the style and pace of your team," says Sparhawk.

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8. Abusing company policies

"Things not to do range from lying or misleading your supervisor about your work or disclosing company information that should not be publicly available and could put the company at risk. I would encourage interns to see themselves as if they are already full-time employees and to carefully consider all their decisions and how they reflect on them [and] the brand," says Jurkiewicz.

9. Assuming you will remember everything

"As an intern, you are going to get a lot of information, whether it's about assignments, schedules or how to use software. It'll look very bad for the intern if they find themselves asking the supervisor to repeat what they said," explains Berger. "Write everything down so you know you'll be able to keep track."

10. Giving up after a few mistakes

"It can be easy to think about all the ways you might make mistakes, but if you are working hard to produce results then the internship will be worth it," says Jurkiewicz. "Even if you don't get a great rating at the end of your summer, or you realize that the internship was not what you hoped it would be, you will be grateful that you could find these things out during a 'trial' rather than in a committed full-time role."

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