If you want to be a successful trader, you must train yourself with consistent habits to avoid some common pitfalls.  Lack of planning and discipline are bad habits that must be broken early.  When entering a trade you must have both your exit routes already mapped out.  You should simultaneously enter your stop-loss and your limit order to exit.  By assessing your risk, and knowing exactly what your risk is on any particular trade, you can create a profitable trading system for yourself.