10 Things They Don't Tell You About Your First Internship

From punctuality to dress code, here are some intern pointers.

Leave your new employer feeling confident about putting you on the payroll.

"If only I'd known then what I know now..."

This familiar statement particularly applies to careers, where success is mostly achieved through experience, trial and error. What if, instead, you had the inside track on what to expect before an experience began?

For anyone who might start their first internship sometime soon, consider this list the dossier on what you need to know:

[See: 10 Tips to Get the Most Out of Your Internship.]

1. You need to be on time for everything. This one might seem basic, but it's important to underscore. "We're talking about an age group that's around 18 to 26," says Yair Riemer, the vice president of marketing at CareerArcGroup, which is the parent company of the website Internships.com. "Their first internship could be their first professional experience period, and things that might seem very basic aren't yet second nature to them, necessarily."

"When you're in school and going to class, you might show up a few minutes late, and it's not always a big deal," Riemer continues. "But punctuality is important in the workplace. Map out your route, and try it the day before or the week before [starting your internship]. Always show up on time for meetings. It shows that you're reliable and can be trusted with deadlines."

2. Social capital is sometimes more important than ability. Showing what you know is important, because no one wants to work with a ding bat. But there are unquantifiable benefits to being likable in the office. On the short list: It helps boost your morale and that of your colleagues, plus it allows you to stay front-of-mind to receive a full-time position and further promotion opportunities. "When I speak at colleges and high schools I stress the importance of networking and mentorship during an internship," Riemer says. "Ask a colleague to go to lunch with you occasionally, then ask them questions about their career path."

3. You could be an intern for awhile. Internships are a stepping stone to the next stage of a career, but these days, that stone's throw from flunky to full-time is a much longer distance. A job offer isn't guaranteed, and even if it does come along, it could be months or years before a company hires you. The more competitive the industry, the longer you could spend hopping internships. To avoid confusion, "Ask what the specific start and end dates are before you begin working with a company, and find out for sure whether they might consider hiring an intern full-time," says Nathan Parcells, the chief marketing officer for the internship placement firm InternMatch.

[Read: Financial Lessons for Generation Y.]

4. Busy work comes with any job. Look at the bottom of any job description. Do you see the spot where it says "Perform other duties as assigned?" Those duties could range from filing paperwork, to data entry, to taking notes in an important meeting, and no matter how highfalutin your chosen career path or GPA, you won't escape some clerical tasks. "There's a yin and yang to the working world," Parcells says. "Every job comes with some component of administrative tasks, and having perspective on how those tasks [to] help the company overall is important."

Aim for excellence, no matter how mundane the task may be. "There's excellent busy work, and then there's mediocre and sloppy busy work," Riemer says. "If you've been given a data entry assignment, then turn in a spreadsheet that's above and beyond, that's easy to navigate and well organized."

5. It's OK to make mistakes. Always strive to do your best, but remember that internships are designed to offer a learning experience. You're not going to know everything, and you're going to botch things a time or two. That's expected, and a good manager will recognize this, expect this and be patient. Ask questions and for assistance when you're struggling, and ask for feedback for how to prevent making the same mistake twice. "Millennials are a generation with 'I can do everything' personalities, and so they don't always respond to failure well. But bosses expect interns to be on a learning curve, and more learning comes from failure," Parcells says.