[cplease]

By investing in the entire market continuously, and squeezing every spare penny to invest even more when there's blood on the streets.

You don't have to time anything right or pick any winners with this strategy, because you'll invest all the way down and all the way back up. You might not have made money from Jan 1 2008 through Dec 31 2008, but that money would have made a killing subsequently.

Of course if you were out of work in 2008 that is easier said than done.

OTOH If you try to make a killing by shorting, there's an infinite number of ways to end up broke by getting the timing wrong. If you bet everything on picking bottom, you can miss the boat or miss the bottom. Not nearly as risky as shorting, but certainly not as reliable as staying the course.