Buy low and sell high. It's pretty simple. The problem is knowing what's low and what's high.

Many investors seem to have forgotten a hard reality: There are frequent periods when stock markets don't do much.

I learned very early in my investing careers: I better not invest in what I want. I better invest in what's happening in the world. Otherwise I'll be broke - dead broke.

Get inside information from the president and you will probably lose half of your money. If you get it from the chairman of the board, you will lose all of it.

If you want to be lucky, do your homework.

Diversification is something that stock brokers came up with to protect themselves, so they wouldn't get sued for making bad investment choices for clients. Henry Ford never diversified, Bill Gates didn't diversify. The way to get rich is to put your eggs in one basket, but watch that basket very carefully. And make sure you have the right basket.

Acknowledge the complexity of the world and resist the impression that you easily understand it. People are too quick to accept conventional wisdom, because it sounds basically true and it tends to be reinforced by both their peers and opinion leaders, many of whome have never looked at whether the facts support the received wisdom. It's a basic fact of life that many things "everybody knows" turn out to be wrong.