One aspect I have seen that even many good traders don't pay enough attention to is account and trade management. Trade management can be broken down into two parts: before the trade management, and open position management. Before the trade management is about taking decisions on when to enter the market, how much you are willing to lose (setting the stop loss), and at what point do you want to exit the market. Open position management is once you have entered the market and is about when to exit the market, how often to check on your trade, and when to add to an open position. Both parts are equally important to being successful in FOREX trading.
Account management is a more macro outlook on your whole account. Account management is about deciding what leverage to use, what currencies to trade, what percentage to risk per trade, and paying attention to your overall risk and exposure. Account and trade management are not as exciting as the rest of the process of trading, but without them it is very hard to be profitable. A small tweak in account and trade management can really increase your profit, so pay attention to it.