Apart from this common-sense piece of advice, just how does someone stand out enough to get to stick around full-time?
At a very minimum, interns should be on time and dress and behave in a professional manner, says Suzanne Helbig, assistant director of the career center at the University of California, Berkeley.
UC Berkeley recommends interns set regular meetings with supervisors, find a mentor and listen carefully to instructions, and avoid calling in sick because "it will be noticed if you are not at work on important days."
Interns also should take on assignments without complaining, seek out additional opportunities to contribute to the workplace and produce high-quality work. "This is your chance to make a really great impression, and you can ruin that by doing things like being late or doing shoddy work," Helbig says.
There also are a few basic don'ts of internships. Helbig warns interns not to use Facebook at work unless it's part of the job, not to tweet corporate secrets or other proprietary information, and to avoid getting sucked into office politics. Interns also should try not to bring personal drama to the office.
"You want to be a person that people want to work with, so when they're thinking about full-time hiring, you rise to the top of the list," she says.
But in a competitive job market in which the Labor Department estimates there are nearly four people vying for every job opening, interns who want to get hired have to go beyond the basics.
"I'm looking for people who can deal with ambiguity and solve problems even when the situation may not initially be clear," says Betts, who now helps recruit marketing and communication interns.
She tends to offer jobs to interns who show they can take initiative, set priorities and can get projects done.
Making yourself more valuable
Enthusiasm and energy are no longer enough to set interns apart, says Jodi Glickman, a consultant and author of " Great on the Job: What to Say, How to Say It. The Secrets of Getting Ahead."
In this era of increasing workloads, interns must be proactive in coming up with their own projects, finding their own way and figuring out where they can have the greatest impact. "Take a couple of days to get a lay of the land, get an idea of projects people are working on and the priority tasks at hand, and give your boss a couple of options of how you might be able to help," she says.
Glickman recommends interns think about how to add value to a company, fill corporate voids and make themselves integral parts of workplace teams.
"Play to your strengths. If you're a great writer, offer to draft a memo or report. If you're naturally skilled as a graphic designer, offer to review the Power Point presentations," she says. "The key is figuring out how you can put your skills to use in an organization."
Martellino suggests interns who want to stay at their companies treat the experience like an extended interview, making sure to put their best foot forward every day.
The "internship is the new interview," he says. "It used to be that you only had to impress a potential employer for a few hours. Now, it's more like a few weeks."