In HBO's Becoming Warren Buffett documentary, Warren Buffett passes on a few life tips to a group of high school students about the importance of being a good person to becoming successful in business

The same lesson was passed on to Buffett by his father. Buffett calls it the principle of having an "Inner Scorecard." Buffett tells the students:

The big question about how people behave is whether they've got an Inner Scorecard or an Outer Scorecard. It helps if you can be satisfied with an Inner Scorecard.

Quite simply, the focus of playing by your inner scorecard is on taking the higher road and making good choices guided by your core values and beliefs. It trumps the idea of living by the outer scorecard -- an external measure of success dictated by others, which can lead to greed.

Buffett clearly lives by his own inner scorecard -- doing not only what's right, but doing what's right for Buffett. And it has paid off for him to the tune of billions of dollars.

To live by your own inner scorecard may mean having to make some changes in your behavior and daily habits, which could pave the way to success. For example:

1. Do business with the right people.

The Oracle of Omaha says: "After some other mistakes, I learned to go into business only with people whom I like, trust, and admire." Why the focus on the people behind business relationships? According to Buffett, it's simple: "We've never succeeded in making a good deal with a bad person."

2. Keep your focus on the things that truly matter.

Buffett learned a long time ago that the greatest commodity of all is time. He simply mastered the art and practice of setting boundaries for himself. The mega-mogul said:

The difference between successful people and really successful people is that really successful people say no to almost everything.

This advice speaks directly to your inner scorecard. It suggests simplifying our lives by saying no over and over again to the things that don't serve us and remaining focused on saying yes to the few things that truly matter.

3. Invest in yourself.

Never stop improving yourself, expanding your knowledge, or acquiring new skills, because, according to Buffett, "investing in yourself is the best thing you can do. Anything that improves your own talents." He adds, "If you've got talent yourself, and you've maximized your talent, you've got a tremendous asset that can return 10-fold."