To improve your mind’s strength and discipline, focus on controlling your thoughts. Thoughts can be controlled and are not as spontaneous as people think they are. Make use of a mantra at least 30 times a day.
For example “I am more than I appear to be, all the world’s strength and power rests inside me”. Blend this mantra with the process of creative envisioning. Go to a quiet place and close your eyes while sitting down. Don let your mind wander. Keep your body still, as the surest sign of a weak mind is a body that cannot rest. Repeat the mantra aloud over and over. While you do so see yourself as a disciplined, firm person, fully in control of your mind, your body and spirit. This technique has been taught by the spiritual teachers of the East for centuries. It is still around today for one reason : because it works.
Start using your willpower on a regular basis. If you don’t feel like doing something – have the willpower to do it. Try maybe to keep silent for a day if possible. This will discipline your mind. Don’t walk the path of least resistance. Build up momentum via smaller victories.