1. There is no investment rule that always works.
If there was one single rule, which always worked, everybody would in time follow it and, therefore, everybody would be rich. But the only constant in history is the shape of the wealth pyramid, with few rich people at the top and many poor at the bottom. Thus, even the best rules do change from time to time.
2. Stocks always go up in the long term.
This is a myth. Far more companies have failed than succeeded. Far more countries' stock markets went to zero than markets, which have survived. Just think of Russia in 1918, all the Eastern European stock markets after 1945, Shanghai after 1949, and Egypt in 1954.
3. Real Estate always goes up in the long term.
While it is true that real estate has a tendency to appreciate in the long run, partly because of population growth, there is a problem with ownership and property rights. Real estate in London was a good investment over the last 1000 years, but not for America's Red Indians, Mexico's Aztecs, Peru's Incas and people living in countries, which became communists in the 20th century. All these people lost their real estate and usually also their lives.
4. Buy Low and Sell High.
The problem with this rule is that we never know exactly what is low and what is high. Frequently what is low will go even lower and what is high will continue to rise.
5. Buy a basket of high quality stocks and hold!
Another highly dangerous rule! Today's leaders may not be tomorrow's leaders. Don't forget that Xerox, Polaroid, Memorex, Digital Equipment, Burroughs, Control Data were the leaders in 1973. Where are they today? Either out of business or their stocks far lower, than in 1973!
6. Buy when there is blood on the street.
It is true that very often, bad news provide an interesting entry point, at least as a trading opportunity, into a market. However, a better long term strategy may be to buy on bad news, which has been preceded by a long string bad news. When then the market no longer declines, there is a chance that the really worst has been fully discounted.
7. Don't trust anyone!
Everybody is out to sell you something. Corporate executives either lie knowingly or because they don't know the true state of their business and the entire investment community makes money on you buying or selling something.
8. The best investments are frequently the ones you did not make!
To make a really good investment, which will in time appreciate by 100 times or more, is like finding a needle in a haystack. Most "hot tips" and "must buy" or "great opportunities" turn out to be disasters. Thus, only take very few investment decisions, which you have carefully analyzed and thought about in terms of risk and potential reward.
9. Invest where you have an edge!
If you live in a small town you may know the local real estate market, but little about Cisco, Yahoo and Oracle. Stick with your investments in assets about which you may have a knowledge edge.
10. Invest in Yourself!
Today's society is obsessed with money. But the best investments for you may be in your own education, in the quality of the time you spend with the ones you love, on your own job, and on books, which will open new ideas to you and let you see things from many different perspectives.
"Regrets I have always taken full responsibility for my actions and never blamed anybody else for what went wrong. As a result I have no regrets. However, lending money to friends has been a disappointing experience since neither has ever any of the money lent ever been returned nor did the friendship continue!" - by Mark Faber
