If you're watching with the eyes of an entrepreneur, the true star of Mad Men isn't really Don Draper, Joan Holloway, or Peggy Olson. It's not even the 1960s. The true star of Mad Men is the advertising firm itself.

Entrepreneurship is a roller coaster, and it's hard to think of a television show that has dramatized that better than Mad Men. Over the course of six seasons, viewers have watched the firm's partners battle for business, come to blows, grow big, get acquired, fall apart, relaunch as a start-up, lose key clients, gain even better clients--and most recently, merge with a rival.

Your business life may not come with quite as many cocktails, or quite as much sex. But when it comes to what it takes to build a business and keep it humming, the show has demonstrated some key lessons of entrepreneurship.

1. It's not who you know. It's who you get to know.

So, you've filled out your LinkedIn profile completely and you go to industry meetings with a stack of business cards? That's nice.

Don first got hired at the agency after meeting Roger, engineering a daytime bender, and then showing up the next day to convince Roger he'd offered Don a job but had been too drunk to remember doing it. That's some aggressive networking.

More recently, Sterling used a fling with an airline stewardess (that's what they were called then), who tipped him off on midwestern executives flying to New York to interview advertising agencies. He hops on airplane trips to meet and befriend them--all in the name of drumming up business.

That kind of networking is probably the second-most important impact on the fictional agency's success. Its account executives are willing to do almost anything to meet decision-makers, develop rapport, and keep them happy.

2. Customers don't know what they want until you show them.

If networking was the second-most important lesson, this is the most important.

Whatever you call the firm (its post-merger name hasn't been revealed as of this writing), much of its success in early seasons was due to creative director Draper's ability to see beyond what clients and customers said they wanted, and understand instead what they truly needed.

In a famous episode from Season 1, he saw that the cool thing about the then-brand-new slide projector wasn't its technology, but the fact that customers longed to connect with their pasts. (The scene where he pitches the client is worth watching.)

That kind of empathy requires truly understanding the client--maybe even better than the client understands him or herself.

3. Perception often trumps reality.

Don's stock in trade is deception--in his messy personal life, for sure (he's not only a hounddog; he's literally living another man's life), but also in business. He and many of the other characters spend much of their time trying to shape reality into what they wish it really were.

When the firm was struggling a couple of seasons ago, and Roger accidentally invited their biggest client to the office Christmas party, they cranked up the tempo "from convalescent home to Roman orgy" to make it seem as if they were doing very well. Advertising itself is largely about perception. To take a recent example, there's the Fleischmann's commercial that Don and his new creative partner, Ted Chaough, came up with: a farmer's wife forgoing the fresh butter from their dairy cows and spreading margarine on her breakfast (as if that would ever happen).

I think this brings up a very fine point: So much of entrepreneurship is about salesmanship, and so much of salesmanship is about managing perception. The difference between fiction and life, I suppose, is that in real life if you squander your credibility, it's much harder to regain.

4. Details matter, but vision matters a little more.

One of the big plot lines for the remainder of the series (the show ends next year) is likely to be about complications from the merger with a competing firm.

Fast growth through acquisition is what you might call a "good problem," but it's clear already that the details are going to drive the drama. From fitting everyone into the physical space, to growing and shrinking staff, to figuring out how the big personalities involved will get along, Mad Men looks as if it will face many of the same management and administrative challenges that any growing business faces in real life.

As that unfolds, it might be easy to forget that driving that kind of major plot development--either on a TV show or in real life--often requires bold vision.

Two episodes ago, sitting in a hotel bar the night before pitching Chevy, Don and his rival Ted decided on-the-spot to merge their firms. They stayed up all night, according to the story, won the carmaker's business--and left it to others to clean up the mess and wrap a pretty administrative bow on it.

5. Drink to excess and cheat on your spouse.

Okay, I'm kidding about this one. But if there's one thing the show's characters seem to do besides run an ad agency, it's drink a ton of alcohol and sleep around. These aren't exactly keys to success, and I'm not advocating them. But they do make for good television.