Most of the time, failure in trading is due to lack of harmony between your trading rules and your personality. And a big part of your trading rules will include dealing with when to offset both losers and winners.

If you begin to lose money, the rule is to get out. The Chinese have a proverb: "If there is a hole in the boat, you don't drill another hole to let the water out." Don't add more funds to your account to maintain a position. Offset the position and go to cash. A huge benefit is that you'll be able to think more clearly after you’re out of a losing position because it's hard in the beginning to make smart financial decisions when you are under duress.

Importantly, you should begin to see that there are two sides to both the financial coin and the emotional coin in trading. The feeling that you get from the possibility of doubling your money or more is “heads,” while “tails” is when you get wiped out. 

Remember this equation: Emotions >> Judgment >> Behavior >> Results.  As in life, so in trading.