I think the strongest edge one can have is to be able to invest independent of any market sentiment. If a stock looks cheap, and according to your research it is cheap, then you need to be able to ignore any market sentiment regarding that stock and buy it anyway.<p>It is far too easy to get wrapped up into wanting the <i>best</i> possible return by buying at the lowest price, and selling at the highest price. The reality is that's near impossible. However, buying companies that by the numbers indicate a 20% return, even if they night get cheaper in a crash, is a decent way to actually get a 20% return. The problem is those kinds of investments only show up with severe uncertainty and negative sentiment. By the time they feel good to invest in the price has reflected that change in sentiment.<p>Of course, this all presupposes skill at evaluating these businesses accurately and reliably, so losers don't drag you down when the negative sentiment is actually correct :/.