It's all about hunting pips 
by study & strategy,
not by guessing or gambling

The 25 Point for Successful Trading


We have all violated this rule. However, it should be our goal to try harder not to violate it in the future. What we are really talking about here is the greed factor

The market has rewarded you by moving in the direction of your position however, you are not satisfied with a small winner. Thus you hold onto the trade in the hopes of a larger gain, only to watch the market turn and move against you. Of course, inevitably you now hesitate and the trade further deteriorates into a substantial loss.