This is how Warren Buffett manages 360,000 Berkshire Hathaway employees

Self-made billionaire Warren Buffett, the world's second-richest man after Bill Gates, recently spoke about how he manages Berkshire Hathaway's over 360,000 employees.

"We count very heavily on principles of behavior rather than loads of rules," he said at his annual shareholders meeting held at CenturyLink Center in Nebraska to an estimated 30,000 people in attendance.

That's sound advice from Buffett, 86, and exemplifies a core belief of his: to challenge himself and others to act with integrity, work with focus and always learn.

Here are some of Buffett's top business principles that he's offered over the years.

Act with integrity

The investor once said, "It takes 20 years to build a reputation and five minutes to ruin it. If you think about that, you'll do things differently."

Here, he suggests you should always behave with a sense of moral character. Otherwise, a career or company can be easily ruined by one bad decision.

Don't overextend yourself

Buffett also advises not to overextend yourself. If you do, he suggests, your results will suffer. "The difference between successful people and really successful people is that really successful people say no to almost everything," he's said.

Educate yourself before taking risks

The "Oracle of Omaha" is a proponent of learning as much as possible about a business and taking calculated risks before investing. "Risk comes from not knowing what you're doing," he's said.

In another famous quote, Buffett counseled, "never invest in a business you cannot understand," underscoring that you should only invest in companies that you've researched and have a firm grasp on.

During the annual meeting, Buffett talked about a wide range of topics, and he even gave some advice to millennials looking to have a successful career.

Editor's Note: This article has been updated.