You overcome by being mindful of what God's Word says about you. When you are Word minded, your are spiritual minded because God's words are spirit and life (John 6:63). In your spirit, you are completely changed, eternal, sanctified, holy and perfected forever. As Jesus is--so are you! If you would dominate yourself with those thoughts, all it would produce is life and peace.
If you mind the things of the flesh, then you will be after the flesh and the physical realm will dominate you. In other words if you are having something other than life and peace, then you are not focusing on His word. In order to release God's power in your life you must overcome the flesh by continually focusing your mind on who you are and what you have in the spirit.