A huge mistake is to marry your trades, get emotionally attached to them, so that every pip lost breaks your heart.
The problem is that we are all humans and it is very hard to get rid of emotions especially when you see your hard earned dollars go up in smoke.
The only therapy I could find is simple - stick to the rules of your strategy and stops and do not change them no matter what. If you still loose money for like 30 trades in a row switch to demo and only start live again when you have some success on demo account.
Hope this makes you a better trader,
Mike