In 30 years at Fortune, I’ve interviewed CEOs and billionaires and other titans about what makes them succeed. Here are 10 things I’ve learned, plus wisdom from Warren Buffett.

The best career advice is universal. It applies to a CEO of a Fortune 500 company and to a kid aspiring to make it through college.
I tried to keep this in mind last week when I spoke at Allentown Central Catholic High School, which in 1978 sent me on my way from Pennsylvania to what has turned out to be a thrilling and very satisfying life and career. I told the CCHS students, who packed Rockne Hall for inductions of their new Student Council and class officers, that I’ve spent the past 30 years at Fortune “going to school on success.” That is, my job profiling some of the world’s most successful people–from Oprah Winfrey to Yahoo  YHOO -0.26%  CEOMarissa Mayer to Rupert Murdoch  NWS 0.00%  to Melinda Gates–is to learn and explain what makes these extraordinary people win and adapt to all sorts of challenges. I pared my message to 10 pieces of advice, which include a few obvious truths and, I hope, some enlightening points that are universal.
1. Don’t plan your career. Most of the really successful people I’ve met and interviewed these past 30 years at Fortune had no clue what they wanted to do when they were in high school or even in college. They stayed flexible and open to possibilities.
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2. Forget the career ladder; climb the jungle gym. In a world that’s unpredictable and changing faster than ever, who knows what tomorrow’s ideal jobs will be? Think of your career as a jungle gym. Sharpen your peripheral vision and look for opportunities over here or over there, and swing to them. Facebook  FB 1.76%  COO Sheryl Sandberg kindly credits me in Chapter 3 of her best-seller, Lean In, for introducing the concept of the jungle gym.
3. Pick people over pay. Work with good people who are smarter than you are, so you can stay stimulated and learn everyday.
4. Do every job as if you were going to be doing it for the rest of your life. If you spend your time thinking about what you want to do next, you’re not fully focused on your current assignment. And unless you focus, you won’t compete successfully with people who are “all in.”
5. Do the job that you’re supposed to do, but think: What’s not getting done? Always consider how you can contribute to the bigger whole — and don’t be afraid to stumble. I wrote a 1995 cover story called “So you fail, so what!” Today, recovering from failure is a badge of honor that bosses want to see in people they hire.
6. Be curious. Everyone you meet is worth learning from. People derail in their careers, studies show, when they stop learning. Yes, continual learning matters more than where you go to school or how many degrees you rack up.
7. Be nice to everyone. As you get older, you’ll have fewer degrees of separation with more and more people. Who knows how someone who doesn’t matter to you today might matter critically tomorrow? Don’t burn any bridges. Build your bridges now to last forever.
8. Listen. Listen more than you talk. I was shy in high school. I’m still a closet introvert, but I’m a good conversationalist because I’m extraordinarily interested in people, I ask questions (sometimes too many) and I listen carefully. Listening to someone carefully is giving them a gift.
9. To lead, line up your followers. Leadership has no long-term value without followers on track to become as strong as you are. Show a generosity of spirit that makes people want to work with you, because they know you’ll make them better.
10. Be honest and true. If people are in a foxhole with you, do they trust you to protect and help them? Make sure they do completely, by doing what you say you’re going to do, always.
I closed my talk with wisdom from Warren Buffett, who told me during an interview last year how he defines success. The Berkshire Hathaway  BRK.A -0.33%  chief actually has two definitions: 1. Success is having what you want and wanting what you have. 2. Success is having the people whom you love love you. Isn’t it reassuring that one of the wealthiest men in the universe doesn’t equate success with money?