Berkshire Hathaway (NYSE:BRK-A) (NYSE:BRK-B) CEO Warren Buffett is unquestionably one of the best investors of all time. Over a span of decades, he's built Berkshire into a $500 billion masterpiece of American capitalism, delivering fortunes to shareholders along the way.

Buffett is also extremely generous, in terms of both his charitable donations and the wisdom he continues to share with the world. Here are 10 of his greatest lessons -- all of which can help you become smarter, happier, and richer.

Warren Buffett.

Warren Buffett. Image source: The Motley Fool.

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

Integrity matters -- both in business and in life.

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

Choose and defend your priorities, or others will choose them for you.

3. "I am a better investor because I am a businessman, and a better businessman because I am an investor."

The insights you gain from building a business can give you an edge when you invest. The reverse is also true.

4. "It's far better to buy a wonderful company at a fair price than a fair company at a wonderful price."

High-quality businesses purchased at premium prices often produce superior returns than lower-quality companies bought at cheaper prices.

5. "The key to investing is not assessing how much an industry is going to affect society, or how much it will grow, but rather determining the competitive advantage of any given company and, above all, the durability of that advantage."

Your long-term investing success will largely come down to this: Can you determine which businesses are likely to win -- both today and in the future? If you can, you will generate fortune-building returns. If you can't, keep learning until you can.

6. "I will tell you how to become rich. Close the doors. Be fearful when others are greedy. Be greedy when others are fearful."

Protect yourself during market bubbles by scaling back your purchases and raising cash. And when the markets eventually crash, amplify your gains by deploying that cash and buying aggressively.

7. "The most important quality for an investor is temperament, not intellect. You need a temperament that neither derives great pleasure from being with the crowd or against the crowd."

It's not about following the herd or being a contrarian. It's about being right -- and being able to keep your bearing when others tell you you're wrong.

8. "The stock market is a no-called-strike game. You don't have to swing at everything -- you can wait for your pitch."

You don't need to have an opinion on every potential investment. Instead, stay within your circle of competency and invest in the businesses you understand well, for that is where your edge lies.

9. "The most important thing to do if you find yourself in a hole is to stop digging."

Sometimes you will find yourself in a bad situation, investment-related or otherwise. What should you do? Stop and reevaluate. Then, adapt, improvise, and overcome.

10. "You only have to do a very few things right in your life so long as you don't do too many things wrong."

Avoid the big mistakes, and you will eventually find success.