You need to always manage your risk properly. If you do not control your risk on EVERY single trade, you open the door for emotional trading to take hold of your mind, and I can promise you that once you start down the slippery slope of emotional Forex trading, it CAN be very hard to stop your slide, or even recognize that you are trading emotionally in the first place. You can largely eliminate the possibility of becoming an overly-emotional trader by only risking an amount of money per trade that you are 100% OK with losing. You should EXPECT TO LOSE on any given trade, that way you are always aware of the very real possibility of it actually happening.
Leveraged trading in foreign currency or off-exchange products on margin carries significant risk and may not be suitable for all investors. We advise you to carefully consider whether trading is appropriate for you based on your personal circumstances. Forex trading involves risk. Losses can exceed deposits. We recommend that you seek independent advice and ensure you fully understand the risks involved before trading.
Since the market is made by each of the participating banks providing offers and bids for a particular currency, the market pricing mechanism is based on supply and demand. Because there are such large trade flows within the system, it is difficult for rogue traders to influence the price of a currency. This system helps create transparency in the market for investors with access to interbank dealing.