FORTUNE – They’re the generation brought up on Facebook. Some have never known a world without the Internet. The innermost details of their lives have been exhaustively Instagrammed, and they get their news from Twitter, not TV.

But when it comes to using social media at work, millennials — the generation whose birth years can range anywhere from 1980 and 2000 — can be surprisingly, even dangerously, unprepared. “Because somebody grows up being a social media native, it doesn’t make them an expert in using social media at work,” says William Ward, professor of social media at Syracuse University’s S.I. Newhouse School of Public Communications. “That’s like saying, ‘I grew up with a fax machine, so that makes me an expert in business.’”

According to Ward, who has 13,500 Twitter followers and teaches a series of popular undergraduate and graduate courses on social media at the university, millennials are lacking in a number of critical areas. While they’re very good at connecting with people they already know, they often fail to understand the professional opportunities and pitfalls posed by networks like Twitter (TWTR), Facebook (FB), LinkedIn (LNKD), and Instagram.

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Combined with some of the other predispositions of Generation Me — idealism, entitlement, a need for instant gratification, and recognition — this can be a recipe for trouble. “Companies hire millennials because they think they’re good at social media. Then their bosses discover they don’t have those skills and get frustrated,” Ward says, noting that social media expectations are often higher for millennials than for older workers, who may be just as inept.

For students and recent grads entering the workforce, some social media 101 is definitely in order. In particular, career-minded millennials desperately need to brush up on these five social media skills:

Knowing when to hit the bleep button

Last September, Business Insider attracted attention for firing its chief technology officer, Pax Dickinson, because of comments he made on his personal Twitter account. While Dickinson’s Tweets on women and minorities were especially offensive, the situation hints at a larger issue. Millennials sometimes fail to appreciate that personal profiles can have professional repercussions. Twitter, Facebook, and other networks are largely public platforms; comments made can — and often do — get back to bosses. As the Dickinson case shows, few employers are eager to associate themselves with off-color or offensive content, even when it may be intended as a joke.

Using social media to actually save time

According to a 2013 Salary.com survey, the most frequently visited personal website at work is — you guessed it — Facebook. As networks proliferate — and millennial employees not only check Facebook but also post on Twitter and browse Instagram and more — social media has the potential to be a devastating time-suck. Yet it can also be a time saver in the office. A recent McKinsey report notes that social media has the potential to save companies $1.3 trillion, largely owing to improvements in intra-office collaboration. Internal social networks like Yammer enable employees to form virtual work groups and communicate on message boards. Instead of endless back-and-forths on email, co-workers can post and reply in continually updated streams. None of this is revolutionary, but millennials are often still in the dark on ways Facebook-like innovations are being taken behind the firewall.

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Understanding how to crunch the numbers

While millennials often have an intuitive understanding of what resonates on social channels (hard to go wrong with cat GIFs), quantifying what works and what doesn’t is another matter. Should the success of a Twitter campaign be measured on the basis of re-tweets, mentions, replies, referral traffic, or sales leads? What are the best times of day to post on Facebook, and what is the optimum post frequency? Which analytical tools are best for crunching the numbers? While social media is about authentic human interaction, it’s also an arena where data can easily be collected and applied to improve results. Knowing what data to look for, where to find it, and what to do with it separates real experts from mere social natives.

Mastering the multi-network shuffle

It’s one thing to be a Twitter guru or have a huge LinkedIn following. The real talent lies in orchestrating different platforms to work together and in understanding the niche each fills. Visual networks like Instagram and YouTube, for instance, are increasingly the foundation of campaigns by social-savvy brands like Nike (NKE), Red Bull, and Mercedes. Catchy images and videos are, in turn, seeded onto traditional text-based networks like Twitter and Facebook. From there, links lead viewers back to blogs and company pages, sending customers spiraling deeper into the sales funnel. Meanwhile, uniform hashtags across platforms help unify and track the overall campaign. Even millennials with deep social credentials often fail to understand the profound multiplying effects of integrating different networks.

Networking professionally on social media

By the time millennials graduate from college, many have dutifully filled their LinkedIn profiles with part-time positions, internships, extracurriculars and academic accomplishments. But the network’s true job-finding power is often overlooked: Hiring managers and CEOs who would normally be out of reach are often just a connection or two away. In fact, you don’t need to be connected at all. A paid feature called InMail, for instance, enables users to send emails directly to any one of LinkedIn’s 277 million members. Truly enterprising job seekers can hunt down big fish like Richard Branson, Bill Gates, and Deepak Chopra, then send a pitch straight to their inbox. Notoriously footloose millennials — forever in search of the next job opportunity — might well take this tip to heart when searching for greener professional pastures.

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Of course, amassing these skills is no short order, and millennials aren’t the only offenders. “The real problem is that we expect people to know these skills without providing any training,” social media professor Ward says. As the number of social networks expands and platforms are used in more sophisticated ways, it’s unreasonable to expect anyone — even the most plugged-in users — to just intuitively get it.

For millennials competing in a tight market, these skills — unheard of just a decade ago — can mean the difference in finding and keeping a job. “Students using digital and social media professionally in an integrated and strategic way … have an advantage,” Ward says. “[They’re] getting better jobs and better internships …”

 Ryan Holmes is founder and CEO of HootSuite, a social media management tool for businesses.