Delta Air Lines CEO Ed Bastian has a simple piece of advice for anyone looking to get ahead in their career: Focus on acing your current responsibilities, without thinking too much about your next promotion or job.

Bastian, 67, credits his own professional success — growing from an auditor at PwC to an executive at companies like PepsiCo, Acuity Brands and Delta — to that simple mindset.

″Do a great job with what you have," he recently told LinkedIn's "This Is Working" podcast. "The job that you have, I learned early in my career, is the most important job to you at that time. And do a great job at that."

Ambition is a desirable trait in employees, Bastian added — but sometimes, being eager to climb the corporate ladder can cause people to "take their eyes off the job at hand." To your boss, you may appear distracted or uninterested in your current role, making you a worse candidate for career advancement.

Bastian's advice stems from personal experience: Doing his best in each job he held, and focusing only on the opportunities immediately ahead of him, ultimately led him to his current position, he said. If he had a dream job early in his career, it certainly wasn't running Delta, he noted.

"I'm the last person that thought I'd be sitting in this seat," said Bastian. "I did not set my aspirations to be the CEO of an airline ... I'd never been on an airplane [until] I was 25."

The 1-word trait successful people share

Ultimately, Bastian's advice boils down to a single word: effort. The effort you put into your role determines what you get out of it, he said.

Good bosses notice effort, said Bastian. Bad ones might not, or worse: They could consider you so irreplaceable that they won't promote you out of your current position. If you're in that situation, you can reach back and develop your fellow colleagues — or, if applicable, even interns — so your boss eventually recognizes them as able to fill your shoes, author and leadership expert Jo Miller recommended in a 2015 LinkedIn post.

"Don't be that individual who climbs the ladder, kicks the ladder away, and lets it land on everyone else," Miller wrote.

Bastian isn't the only successful executive to preach effort. Billionaire entrepreneur and investor Mark Cuban, for example, recommends taking initiative to solve problems, even when you aren't asked to — exhausting every possible option to find answers.

"The one thing in life you can control is your effort," he said last year in a LinkedIn video post published by entrepreneur and VC investor Randall Kaplan. "And being willing to do so is a huge competitive advantage, because most people don't."

For Amazon CEO Andy Jassy, the key is jumping at opportunities to learn how to do your job better. "You have to be ravenous and hungry to find ways to learn," he said last month, in a video posted by Amazon.

However you embody it, effort can set you apart from your colleagues and make you a stronger candidate for raises or promotions down the line, said Bastian.

"Do a great job and I guarantee, I know at Delta, you'll be seen, you'll be heard and people will take notice," he said.

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