Here’s an interesting quote by Charles Haanel:

“Realize the fact that the essence and soul of all things is spiritual and that the spiritual is the real, because it is the life of all there is; when the spirit is gone, the life is gone; it is dead; it has ceased to exist.

These mental activities pertain to the world within, to the world of cause; and conditions and circumstances which result are the effect. It is thus that you become a creator. This is important work, and the higher, loftier, grander and more noble ideals which you can conceive, the more important the work will become.

Over-work or over-play or over-bodily activity of any kind produces conditions of mental apathy and stagnation which makes it impossible to do the more important work which results in a realization of conscious power. We should, therefore, seek the Silence frequently. Power comes through repose; it is in the Silence that we can be still, and when we are still, we can think, and thought is the secret of all attainment

Thought is a mode of motion and is carried by the law of vibration the same as light or electricity. It is given vitality by the emotions through the law of love; it takes form and expression by the law of growth; it is a product of the spiritual “I”, hence its Divine, spiritual, and creative nature.

From this it is evident that in order to express power, abundance or any other constructive purpose, the emotions must be called upon to give feeling to the thought so that it will take form. How may this purpose be accomplished? This is the vital point; how may we develop the faith, the courage, the feeling, which will result in accomplishment?

The reply is, by exercise; mental strength is secured in exactly the same way that physical strength is secured, by exercise. We think something, perhaps with difficulty the first time; we think the same thing again, and it becomes easier this time; we think it again and again; it then becomes a mental habit. We continue to think the same thing; finally it becomes automatic; we can no longer help thinking this thing; we are now positive of what we think; there is no longer any doubt about it. We are sure; we know”