If you pause for a moment to listen to your thoughts, you are likely to find that most of the thoughts you have do not register within your consciousness. However, you may observe that you are reacting to these thoughts without you realising it. Take the opportunity to listen to your thoughts as they enter the mind, like an outside observer. Then strive to catch hold of any negative or damaging thoughts before they take hold within your consciousness. Then push such thoughts out of your consciousness, indicating that you do not want them to be part of your life.
In order to master your thoughts, you have to learn to listen to your own thoughts. Skills acquired through Life Force mindfulness, meditation and cognitive practices can all help you to listen to your own thoughts as the impartial arbiter.