An old friend of mine told me this, and I'm paraphrasing...

"Marrkus," he'd say. "When it comes to the stock market, you only need to be right 50% of the time."

"What do you mean?" I'd ask.

Old friend replied, "You see, when you are right you just ride that stock until it is time to sell. But when you are wrong, you can catch it quick and dump it. So when you are right you can make terrific gains, and when you start to lose you can staunch the bleeding before you've bottomed out."

"So that's the trick?" says me.

"That and don't fall in love with any stock no matter how good it has been to you," he said with an air of finality.