Originally Posted by MikeRoth

If you get stopped out that's fine, you win some you lose some, there is literally no one with a 100% track record in stock investments. You're goal is to find a stock that's about to rally, buy in at the bell, if your DD was correct you made profit (typically 10%-50% but 80% or more is not uncommon). If not you stopped out and lost a maximum of 10% of your investment.

The reverse is also true, if a company has terrible earning reports, expect a huge drop, buy those shorts.