You only need a few good stocks in your lifetime. I mean how many times do you need a stock to go up ten-fold to make a lot of money? Not a lot.

The Rule of 72 is useful in determining how fast money will grow. Take the annual return from any investment, expressed as a percentage, and divide it into 72. The result is the number of years it will take to double your money.

If you can't find any companies that you think are attractive, put your money in the bank until you discover some.

My method for picking stocks has never changed. When businesses go from crappy to semicrappy, there's money to be made.

Know what you own, and know why you own it.

When even the analysts are bored, it's time to start buying.

There's no use diversifying into unknown companies just for the sake of diversity. A foolish diversity is the hobgoblin of small investors. That said, it isn't safe to own just one stock, because in spite of your best efforts, the one you choose might be the victim of unforeseen circumstances. In small portfolios, I'd be comfortable owning between three and ten stocks.