This column is about Mad Men, but you don't have to watch the show to understand it (well, at least most of it).

As the show returns for its final half-season (set in 1970), I'm convinced it should be required watching for entrepreneurs. That's because its main character isn't Don Draper, Joan Holloway, or even Peggy Olson. Instead, it's the advertising agency itself.

Here are 13 things anyone who wants to become successful needs to learn from Mad Men.

1. Do the math.

Yay! Some of the main characters are millionaires in the new season--or at least have the potential to be--after McCann Erickson acquires their firm. Yet it seems that they're not really sure how much money they have or what to do with it. Even simple math escapes them at times (at one point, a character remarks that his 20 percent share of a $65 million company would be worth "at least $6 million."
Takeaway: It's hard to achieve success if you don't understand how it's measured.

2. Find your passion.

The characters' personal lives are as tumultuous as ever, but it does seem that they're in a business they are truly passionate about--even if that often comes at the expense of their physical and mental health.
Takeaway: It's easier to be successful if you love what you're doing.

3. Think about structure.

When the show premiered, the agency was a small but established firm. It has since been absorbed into a larger firm, had its partners rebel and launch their own spinoff, and merged with a competitor, and now it has been acquired by one of the largest ad agencies in the world. Some of that is just television drama--but it's also about adapting structure to pursue opportunities.
Takeaway: Never forgo a great opportunity before you've considered if restructuring could help you win and manage it.

4. Find your balance.

This is the flip side of passion--and it's something that most of the characters struggle with constantly. It's why the firm is doing well, but it's part of why both main protagonist Don Draper and his best frenemy, Roger Sterling, have both gone through two divorces during the course of the show.
Takeaway: Is your business really worth your physical health or the death of your relationships?

5. Think bigger and bigger.

When the agency lands an account for an airline, it wants one for a bigger airline. When it lands an account for a car company, it wants one for a more prestigious car company. That insatiable hunger doesn't lead to contentment, but it does seem to lead to success--at least for now.
Takeaway: People rarely succeed greatly without first deciding they want to do so.

6. Quit when you need to.

Things start and end over and over and over on Mad Men. Employees quit (or get fired), clients come and go, and romantic relationships fall apart. And yet with every departure there's another arrival.
Takeaway: Sometimes the most courageous choice is to stop doing what you're doing.

7. Trust your creativity.

Don and Peggy trust their creative side and have the same process. Think as hard as you can about your problem. Then forget about it, and let your creative subconscious do the work. The challenge is that creative people (like Don) often wind up with a lot of other problems as well.
Takeaway: Your mind can be more powerful than you realize.

8. Fake it until you make it.

The whole show starts with the revelation that Don Draper, the main character, has actually stolen a dead man's identity. More recently, when the agency's media buyer realizes a client wants an agency with a computer, he simply lies and says that it has one--and then persuades his peers to buy one. Yes, it's just drama, but almost every time, things work out.
Takeaway: We're all faking it to some degree; why not do so a little more strategically?

9. Maintain detachment.

By and large, the characters are really poor at this, and it's one of the key components of maintaining balance. One character mutilated himself; another freaked out over work and seemed on the verge of intentionally crashing his Cessna. It remains to be seen how easy it will be to achieve detachment for some of the female characters who have found success and responsibility but are still treated in appallingly sexist ways.
Takeaway: Sometimes success comes when you decide it's no longer as important to you.

10. Show your customers what they want.

Throughout Mad Men and in real life, customers--heck, most people--often don't understand what they really want. They focus on tactical objectives without even understanding what their strategic goals are. If you can show them, you can often win their business.
Takeaway: Your job probably isn't just to say yes; it's to provide the benefit of your expertise.

11. Tend to your network.

The characters are both wonderful and terrible at this. On the one hand, Don Draper first got hired at the firm as a result of very aggressive networking with Roger Sterling. On the other hand, Draper is so bad at maintaining relationships that in this season's opener, he doesn't learn of his former girlfriend's leukemia until after she's already dead.
Takeaway: Networks are like banks; you have to make deposits before you can make withdrawals.

12. Move to the sound of the guns.

Last season, it seemed the future was in California. Now it seems maybe it's in hedonism, given all the 1970s free love. Regardless, one of the interesting themes in Mad Men is how aggressively the characters try to change with the times--with varying results.
Takeaway: Nothing portends success like action--except maybe finding a bigger market to begin with.

13. Take care of your people.

This is yet another area in which the main characters are alternately role models and disasters. One of the central relationships in the show is the one between Don Draper and Peggy Olson--who begins as Don's secretary and ultimately becomes his protégé and even for a short while his boss. But on the other hand, the firm treats some of its people horribly, sometimes with wonderfully disastrous results (for example, firing accounts man Ken Cosgrove only to see him become the head of advertising for the firm's biggest client, Dow Chemical).
Takeaway: People remember how you treated them long after they forget everything else about you.