Kevin O'Leary says this ‘simple’ habit can help you land a promotion

Kevin O'Leary: This habit will help you earn a promotion
Kevin O'Leary: This habit will help you earn a promotion

There's no shortage of advice on the best ways to secure a promotion at work. But if you ask Kevin O'Leary, there's only one "simple" thing you need to focus on.

"When you're an employee, you want to make your boss look good," the "Money Court" judge and O'Shares ETFs chairman tells CNBC Make It. "What matters in business is that they look good because you're doing great work."

O'Leary says that when you are assigned a task or volunteer to take on additional responsibilities, you should make sure to make your performance measurable. This can range from asking for a written deadline on a project to setting target metrics that you want to hit.

By having a measurable goal, you achieve "executional excellence" that will be noticed not only by your boss, but by other people around you, O'Leary says. Focusing on performance is especially important for remote workers who have lost the ability to "schmooze around the water cooler at lunch" with their bosses, he adds.

But doing a good job is only half the battle: It's just as important to keep close track of your performance.

A pen and paper is the most valuable tool in your arsenal when it comes to negotiating your next raise or promotion — provided you use it to write down all your accomplishments at work, O'Leary says.

"You don't have to be sophisticated to pull this off. You can just keep a journal — pen and pencil," he says. "It's very simple."

When it comes time to discuss your next raise or promotion with your boss, you won't need to wrack your brain to remember everything you accomplished because you already wrote it all down.

"[Your boss] may not remember, but you do, because you're keeping every single journal entry about the tasks you were given when they were given to you," O'Leary says. "That journal is your record of success and proof that you have executional skills."

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