Tim Cook leads the most valuable company on earth, a company known for creating some of the most innovative products of the past few decades. It has over 145,000 employees and is worth more than $2 trillion. It makes and sells some of the most iconic devices that are used by more than 1.5 billion people, most of whom are more like a fan club than customers.

Jeff Bezos leads a pretty big company himself, and it has made him the richest person on the planet. That company, Amazon, might have more of an impact on the daily lives of more people than any other company, ever. It's where we go for everything from toilet paper to books to anything else that can fit in a box and be delivered to your door. It also powers many of the other services that people use every day, like Netflix, and the latest social media sensation, Clubhouse. 

You can imagine that it takes a lot to keep all of those trains running on time and in the right direction. Here's the thing, though. There's no possible way for someone like Tim Cook or Jeff Bezos to deal with all of the things that go into running their respective companies. There's just far more than an individual could possibly do.

And yet, Cook and Bezos are the perfect examples of a simple principle that makes them two of the most highly productive people: They don't even try. Seriously.

Instead, they focus on what I refer to as the "only you" principle. 

I know, it's a weird name for a leadership principle. That part isn't even important. What is important, however, is the idea that you should do only what only you can do.  

I didn't make up that principle. I've heard it a few dozen times in different places, but the point is that while it might seem counterintuitive, it's actually so simple. The way to get more done is to stop trying to do it all. Seriously. 

The beauty of this principle is that it has two benefits. The first is that it helps you prioritize and manage the limited resource of time that you have each day by helping you focus on what you absolutely need to be doing with your time. The second is that it encourages you to stop thinking that you are the person who should be doing things that could be done just as well, or often better, by someone else. 

As a leader, there are things that only you can do. Only you can make the strategic decisions that determine the direction of your company, for example. Bezos refers to these as "one-way door" decisions. They are high-stakes decisions that, once you make them, you can't just go back through the door. 

The thing is, if you spend your time on other things--things that someone else could be doing--you won't have the time to do the things that your team is counting on you for. Cook is an especially good example of this. 

While he is intensely focused on even the smallest details, he isn't interested in micromanaging things that aren't his strength. For that matter, he's well aware of what his strengths are, and more important, what they aren't. He's never been known as a product design person and when he took over Apple, he didn't suddenly start visiting the design studio every day, as his predecessor, Steve Jobs, was known to do. He continued to trust that that team knew what it was doing. 

Your job, as a leader, is to ask yourself whether the things you're doing are things that only you can do. Often they are. In that case, by all means, keep doing them.

If they aren't, you and your business will benefit as soon as you find someone else who can do them. Even if you can't find someone, it's still often the case that your business will be better off if you let go of the rest, even if that means it just won't get done. 

Find the very best people you can for any given job. Then, give them the resources, encouragement, and accountability to be even better. Then focus on doing the things that only you can do for your business. It's that simple.