Risk management in forex trading lies in prudent use of leverage, lot sizes, stop loss and take profit tools. You have to risk no more than some certain % per trade from your equity, it is the main rule. The second is to maintain profit/loss ratio per trade that should exceed 1. It can be 2:1 or 1.5:1, i.e. you have to cut losses earlier (in terms of pips) than your profitable trades.