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.

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.

Be sure that you are well compensated for illiquidity - especially illiquidity without control - because it can create particularly high opportunity costs.

The way to maximize outcome is to focus on the process.

You must buy on the way down. There is far more volume on the way down than on the way back up, and far less competition among buyers. It is almost always better to be too early than too late, but you must be prepared for price markdowns on what you buy.

A margin of safety is achieved when securities are purchased at prices sufficiently below underlying value to allow for human error, bad luck, or extreme volatility in a complex, unpredictable and rapidly changing world.

The prevailing view has been that the market will earn a high rate of return if the holding period is long enough, but entry point is what really matters.