Investing is the intersection of economics and psychology. The analysis is actually the easy part. The economics, the valuation of the business isn't that hard. The psychology - how much do you buy, do you buy it at this price, do you wait for a lower price, what do you do when it looks like the world might end - those things are harder. Knowing whether you stand there, buy more, or whether something has legitimately gone wrong and you need to sell, those are harder things. That you learn with experience, by having the right psychological makeup.

All investors must come to terms with the relentless continuity of the investment process.

It's awful to have a depression, but it's a great thing to have a depression mentality because it means that we are not speculating, we are not living beyond our means, we don't quit our job to take a big risk because we know we might not get another job. There is something stable about a country, a society built on those values.

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.

Most institutional investors feel compelled to swing at almost every pitch and forgo batting selectivity for frequency.

Value investing is simple to understand but difficult to implement. Value investors are not supersophisticated analytical wizards who create and apply intricate computer models to find attractive opportunities or assess underlying value. The hard part is discipline, patience, and judgment. Investors need discipline to avoid the many unattractive pitches that are thrown, patience to wait for the right pitch, and judgment to know when it is time to swing.

Short-term performance envy causes many of the shortcomings that lock most investors into a perpetual cycle of underachievement. Watch your competitors not out of jealousy but out of respect and focus your efforts not on replicating others' portfolios but on looking for opportunities where they are not. The only way for investors to significantly outperform is to periodically stand far apart from the crowd, something few are willing, or able, to do.