Want to Be Successful? Follow This 1 Rule

If there were some way for you to download decades of my experience in the business world and sort through the individuals who have had great success bringing real products to market, you’d find something very interesting.

You’d find a lot of very competent, talented, smart, ingenious, driven people who work very hard at their jobs. And the one thing they care about most is helping to deliver groundbreaking products and services that customers prefer over the competition.

One more thing they’d all have in common: a specific area of functional expertise. Whether it’s product development, operations, marketing, finance, or an entire market, there is always one thing they do best. The same is true of nearly every successful entrepreneur you’ve ever heard of:

Facebook founder Mark Zuckerberg is a coder. So is Google CEO Larry Page. So was Bill Gates.

Before and after cofounding PayPal, Peter Thiel ran hedge funds. Sure, he has a law degree, but like Warren Buffett and Charles Schwab, his expertise is in investing.

Steve Jobs was more of a marketing genius. Likewise, Starbucks founder Howard Schultz has a head for marketing.

Apple’s current CEO Tim Cook is an operations guy.

Whole Foods founding CEO John Mackey has always been into food, especially healthy food.

As for Salesforce.com CEO Marc Benioff, as far back as high school he was all about software.

Related: The Unexpected Benefits of Doing the Unexpected

I started out in engineering but migrated to marketing. Although I’m now a business consultant and writer, I’m still a marketing guy. That’s what I do best.

I could go on but I’m sure you get the point. Everyone starts out doing something and some of us end up running the whole show, but somewhere in between, successful people always find the one thing they do best. And that becomes a pivotal point in our careers.

While I’m tempted to say that once you find it, you pretty much know, I can’t say that for sure. It was true for me and of everyone else I’ve ever asked about it, but I’m sure some only know in hindsight, long after the fact.

Still, there is a catch. As far as I know, this is true only of highly driven people. I suspect the reason is they make it their mission in life to find a place where their talents can shine and they can make their mark on the world. They search until they find it. That pursuit speaks to their motivation, focus, discipline, and work ethic.

If you have those qualities, I believe you will find what you’re looking for. Sooner or later, I think we all do. But one thing’s for sure. That one thing is always a market or functional expertise. If not, then by definition it’s not marketable and you won’t be successful, at least not from a business standpoint.

Related: 10 Behaviors of Genuine People

Of course, your one thing could be some sort of humanitarian cause. It doesn’t have to be a moneymaker. But make no mistake, if you want to be successful in business, you have to find that one thing you do best.

Speaking of which, one article making the rounds makes the ridiculous claim that “entrepreneurs are generalists.” There are two problems with that. First, the single European study it references was actually a student survey. It involved no entrepreneurs. Not one.

Second, the authors of the study, although it actually hurts for me to call it that, wrote, “… mere computer nerds are not likely to become entrepreneurs …” Really? Could they be more wrong? What about Gates, Wozniak, Page, Zuckerberg, and hundreds of other geeks who founded great companies?

That’s actually as good an example as any to provide a word of caution. The Internet is literally littered with fads, pseudoscience, BS claims, ludicrous surveys, and content mills that will sell their souls for some clicks and eyeballs. Getting into that sort of thing does not count as an expertise. Not even close.

Truth is, if real entrepreneurs wasted their precious time on all that online nonsense instead of focusing on finding and developing the one thing they do best, there would be no Microsoft, Apple, Google, or Facebook. There would be no Silicon Valley. And there would be a lot fewer successful entrepreneurs.

Related: Want to Be Successful? Quit Wasting Your Brain.

This article originally appeared on Entrepreneur.com.