The safest place to stretch the truth tends to be in the parsley parts of a résumé, things like hobbies, interests, and foreign languages spoken. That 2004 survey of HR professionals, for example, found that only 2 percent reviewed applicants' claims about published articles and speaking engagements in every instance. Which means the average sleuth isn't likely to bother with those academic prizes you've collected or your facility with Sanskrit. "Unless the job requires Sanskrit," Jautz says, "we won't check."

Feel free to juice your salary a bit, too. Like a car buyer looking at a sticker price, prospective employers almost always assume a 10 percent markup.

Exhibit A: The handiwork of Adam Wheeler, the 23-year-old former Harvard student accused of lying his way to $45,000 in scholarships.

One thing most HR people are conscientious about is checking references. But let's face it, they don't exactly have the resources of the FBI. People ask their friends for bogus recommendations all the time. If you're going to do so, just be sure to brief your pals on your day-to-day duties. "You can usually tell who's lying by asking what someone did on the job," says Christina Zeller, the director of human resources at Belkin in Los Angeles. "That often holds true when people pad their résumés as well. You ask a guy who says he led a team when he was just on a team, and it's clear that he has little insight into what leaders do."

If you want to be really bold, put the HR department's resolve to the test. A few years back, a Yale student boasted that his application to the school had included a letter of recommendation from the Dalai Lama. Eminent, monstrously busy world figure, residing many, many time zones away—how uncheckable is that?

As counterintuitive as it sounds, though, the best time to start lying about yourself is your first month on the job, right after you've impressed people with your work ethic. "Once we make up our minds about something," says Dan Ariely, professor of behavioral economics at Duke University and author of the best-selling book Predictably Irrational: The Hidden Forces That Shape Our Decisions, "we tend to overlook, excuse, or explain away information that contradicts that belief. We overvalue what we think we know." That explains how Jayson Blair could continue to file phony stories for the New York Times long after suspicions had been raised about his veracity.

When your colleagues are your friends, you can use social media to establish your singular virtues. Fill your Facebook page with status updates on your volunteer work at the soup kitchen. Tweet about your campaign to read the complete works of Tolstoy.

Really, it's no different from the fish stories you tell the guys over drinks after work. Occasionally you might try unleashing your feminine side, too. "Men and women lie with the same frequency," Feldman says, "but they do it differently. Men lie to enhance themselves; women lie to make the other party more comfortable, using flattery and praise and self-effacement to show that they'll fit in." In other words, while conning your boss into thinking that you came up with your previous employer's entire mobile-phone strategy, take a moment to commend him on his own achievements (thank you very much, Google).