Twitter and Facebook may be able to pay their interns what many of us would hope to earn full time, but for employers outside of Silicon Valley, that's wishful thinking.

More than 4,700 companies across the U.S. are hiring interns right now, according to career database Glassdoor, and very few have anything approaching the tech giants' resources. Is it possible for a company who can't afford to pay its interns minimum wage, much less Silicon Valley prices, to recruit top talent?

Yes, says Glassdoor's senior vice president of people Allyson Willoughby. If you can't offer money, however, you have to provide valuable experiences. Here are her tips for running an unpaid internship program that will nonetheless attract desirable candidates.

1) Offer real world experience.
Internships are valuable because they offer students professional exposure in an industry they want to enter and can often help them land a job down the line. While some companies try and lure free help with the promise of a socially packed summer, the best applicants "want to say they got to help write a case study or shadowed an executive once a month," says Willoughby. "Real world experience is worth just as much, if not more, than money."

Related: The 25 Highest-Paying Companies for Interns

2) Create structure.
Creating an agenda – ranging from a formal training process to something more casual, like a monthly company lunch were interns get to know employees in a more casual setting – can be simple and low-cost way to ensure that they don't get lost in the shuffle.

3) Invest your time.
Even unpaid internships are going to cost your company; it takes a lot of effort to hire, train and supervise an intern. Many companies, Willoughby says, underestimate the amount of time involved in running a successful program. "It's a lot of work. College students, even graduate students, don't have a lot of real world experience. You can't hire them and then magically expect them to start producing like regular employees." Before you even consider offering an internship program at your company, make sure you can spare the extra resources. "Managers need to be willing to give their time to interns," Willoughby says. Like any good relationship, "there needs to give and take for it to work."

Related: 5 Reasons You Need Interns to Build Your Business

4) Look for enthusiasm.
Again, interns are not the same as employees. Many have never worked in a professional work environment before. "A standard interview process may not work perfectly for college students," says Willoughby. They may be nervous; they may flub answers. And most have little, if any, relevant experience. So what does Willoughby look for in an intern? "They're obviously not going to walk in the door and say I've written 500 case studies because they're not at that point in their career," she says. "But if they walk in the door, and tell us what they love about Glassdoor -- how it's transforming the workplace -- then that's a definite selling point." Passion and enthusiasm is paramount (especially if you aren't offering monetary compensation). 

Related: Inside Netflix's No-Intern Policy

5) Recruit.
Interns aren't employees, but that doesn't mean you can't ask them for referrals. "That's how we've gotten some of our best interns," says Willoughby. When Glassdoor hires an especially successful intern, Willoughby will ask if he or she has friends who would be a good fit for the company.

If you do it right, Willoughby says, your internship program will develop a reputation for providing valuable experiences that more than makes up for the lack of pay. Word of mouth is the best form of publicity. Every time an intern leaves happy with her experience at your company, she's going to tell all her friends. But if her entire summer was spent filing documents and fetching coffee? That will circulate quickly, too.

Related: The 16 Biggest Tech Intern Fails