Loss avoidance must be the cornerstone of your investment philosophy.

Value investors will not invest in businesses that they cannot readily understand or ones they find excessively risky. Hence few value investors will own the shares of technology companies. Many also shun commercial banks, which they consider to have unanalyzable assets, as well as property and casualty insurance companies, which have both unanalyzable assets and liabilities.

Successful investors must temper the arrogance of taking a stand with a large dose of humility, accepting that despite their efforts and care, they may in fact be wrong.

Hold cash when opportunities are not presenting themselves.

Value investing by its very nature is contrarian.

Beware leverage in all its forms. Borrowers - individual, corporate, or government - should always match fund their liabilities against the duration of their assets. Borrowers must always remember that capital markets can be extremely fickle, and that it is never safe to assume a maturing loan can be rolled over. Even if you are unleveraged, the leverage employed by others can drive dramatic price and valuation swings; sudden unavailability of leverage in the economy may trigger an economic downturn.

A commodity doesn't have the same characteristics as a security, characteristics that allow for analysis. Other than a recent sale or appreciation due to inflation, analyzing the current or future worth of a commodity is nearly impossible.