There are many reasons why a forex or stock trader fails and looses money. One big reason for losing trades is that the trade should have not been placed in the first place. A stock or currency trader needs to make sure he is prepared to have a losing trade but also knows how to let the winners run. If you are a long term or swing trader then you should know your risk when you place a trade. When you place a trade you should have calculated what to do if the trade goes south and you start to lose money on the trade. Failing to place a stop loss is a mistake.
Another way to look at it is putting in a stop loss actually makes you money. By not having a predetermined stop you will just lose more capitol. Losing traders or new traders will chase the losing trade by buying more of the stock hoping for a rebound. A successful trader lets the trade stop out and then revaluates the position by looking for the next support area to place another trade. There is always another trade to take so walk away from the losing one and save some of your money for the next one. As you begin to trade successfully you will protect and save your trading capital.
You should not add to a losing trade in the hope that it will eventually make you money. This is a mistake a great deal of traders make and wonder why they can't make any winning trades.You can't compete with the big brokers and banks who can stay in trades for months and ride out a bad trade until it bounces off a support area. Remember to keep emotions out of your trades and you will make more money. Controlling your emotions and using stop losses will keep you in the money on most well placed trades.
Forex and stock markets are always changing with news and political events. The price of gold and the dollar can effect both markets. That is why you need to be prepared to trade by doing research and know what news is happing when you are making trades. There are always risks when you place a trade so know what they are and you will be more successful. You should keep an eye on the liquidity and volume in both markets. If the volume is low then you know that any moves will be small. When you have good volume then liquidity makes it much easier to make winning trades. Make sure to revise your trading plan and you will make some money in the forex and stock markets.