The professionals’ “secret” is not a trading rule like “buy the opening breakout if yesterday’s close was at the high.” Each trader has his own trading rules, and each set of rules is equally valid — there is more than one right (profitable) way to trade a market.

You can find trading rules for each style of trading, generally organized according to how long you plan to hold positions. Trading rules can be roughly categorized as belonging to the day-trading style (holding period of minutes), swing trading style (holding period of a few hours to a few days), and position trading (holding period of several days to several months).

The secret is that professionals know the difference between a good loss and a bad loss.