As mentioned in our day trading and swing trading articles, controlling risk needs to be the #1 priority of any trader. To control risk and avoid blowing up your account, you need to adjust the position size of your trades in order to keep your risk of ruin at or close to zero.
In terms of what risk models to use, we highly recommend a fixed % equity risk per trade for the reasons outlined in our Fixed % vs Fixed Dollar Amount Risk: Which is Better? article.
Use our free position size calculator for FX/stocks above to help you find the correct position sizing based on your risk profile.