Probably the most common career advice is "Do what you love!" People love hearing it, even though it's all wrong -- except under very specific circumstances.

"Telling someone to follow their passion can be disastrous," says Cal Newport, author of So Good They Can't Ignore You: Why Skills Trump Passion in the Search for Work You Love (a book I've given to at least 20 people). "That advice has probably resulted in more failed businesses than all the recessions combined ... because that's not how the vast majority of people end up owning successful businesses."

"Passion is not something you follow," Cal says. "Passion is something that will follow you as you put in the hard work to become valuable to the world."

Take Nelson Piquet Jr. He loves racing. Racing is his passion. But passion was not enough.

It's easy to confuse a hobby or interest for a profound passion that will result in career or business fulfillment. The reality is, that type of preexisting passion is rarely valuable.

Don't believe me? Think about something you are passionate about. Or that you were passionate about when you were a teenager. Then apply this test: Will people pay you to do it?

There are plenty of amateur racers. Nelson is a professional: He's driven in some of the top series in the world. He does what he loves, and, more importantly, he's so good he can earn a living doing what he loves.

"Money matters, at least in a relative sense," Newport says. "Money is a neutral indicator of value. Potential customers don't care about your passion. Potential customers care about giving up their money."

Here's another test to apply: the experience test. Nelson started racing when he was young. He also spent countless hours around racing. The same is true where business success is concerned: Passion is almost always the result of a tremendous amount of time and effort.

"The myth of the virtuoso is a problem," Newport says. "In the majority of cases, people didn't think of someone who became a virtuoso as having unusual talent when they were very young."

Instead, most highly skilled people were exposed to something in a way that made it interesting. Take music: Something (a song, an instrument, a teacher, etc.) initially inspired them. In Nelson's case, it was driving -- well, driving anything. Every highly skilled person started learning, and then benefited from what Newport describes as a feedback effect. "If you practice hard, soon you might find you're the best in your group of students," he says. "That's great feedback and it motivates you to keep practicing. Then you're one of the best in a larger group and that's motivating too. Practice and achievement is a gradual, self-reinforcing process."

And that's how Nelson moved up through the ranks. He won races, moved up a level, gained skill, won races, moved up, and so on.

Of course Nelson's path is unusual; there are very few professional race car drivers in the world. Fortunately, for entrepreneurs the playing field is much larger. So if you think there is a market for your passion -- meaning people will pay you for it -- that is enough to get you started. Then doing the work, and working as hard as you can to improve your skills, will give you the feedback you need. Creating a viable product, for example, will motivate you to refine that product, or create even better products. Landing one customer will motivate you to develop more skills so you can land more customers. Winning at one level will motivate you to work hard to work up to the next level and prove yourself there.

The satisfaction of achieving one level of success spurs you on to gain the skills to reach the next level, and the next, and the next.

And one day you wake up realizing that you're doing what you love -- and getting paid to do it.

"The satisfaction of improving is deeply satisfying, as eons of craftspeople will attest," Newport says. "The process of becoming really good at something valuable is a fulfilling and satisfying process in itself ... and is the foundation for a great entrepreneurial career."

Want to love what you do? Pick something interesting. Pick something financially viable -- something people will pay you to do or provide.

Then work hard. Improve your skills, whether at managing, selling, creating, implementing -- whatever skills your business requires. Use the satisfaction and fulfillment of small victories as motivation to keep working hard.

That's how you build a business. That's how you build a racing career. Nelson loves to race, but he gets to race because he is such a valuable commodity to race teams. If he weren't so skilled, they wouldn't hire him.

"Don't focus on the value your work offers you," Newport says. "That's the passion mindset. Instead focus on the value you produce through your work: how your actions are important, how you're good at what you do, and how you're connected to other people."

That's how you get to do what you love. Follow your passions, but make sure that what you're passionate about is a field where you can also make a living.

Doing work you love, over the long-term, requires getting paid to do what you love -- which means being good enough at something other people value enough to pay you for it.