The way to strengthen your mind & will power is through meditation. You do not have to be a sadhu to meditate daily. Meditation is for every one, You do not need to meditate for an entire day like you see on movies. All it needs it just 10min of meditation to keep you sharp.
How can i start meditating? I do not know anything about meditation.
Just sit in a silent place, close your eyes & listen to your breathing, thats enough, you do not need to do anything else, Just ignore the chatter in background of your brain or the voice of your critic, just listen to your breath.
Why does this work.
When you meditate, When you are listening to your breath, Your Critic chatter in the back of your mind will wander around thinking about different things, eventually you will also get instead in it & listen to ur critic & go to dream world instead of concentrating in your breathing. You will suddenly realize that & resume concentrating to your breathing. When you are starting up, you might not be able to go even 2min without this happening. Thats whats supposed to happen, its like a training for your mind. The more you meditate the better results you get. The more you catch yourself wandering in the dream world with ur cretic. the stronger your will becomes.
Over time you will come to notice that the chatter of the critic fades away & you are able to concentrate fully in your breathing.