Man from a psychological standpoint of development is not what he should be. He does not possess the self-mastery, the self-directing power of concentration that is his by right.
He has not trained himself in a way to promote his self-mastery. Every balanced mind possesses the faculties whose chief duties are to engineer, direct and concentrate [...]

Some Mistakes Some People Make. If you waste your time reading sensational stories or worthless newspaper items, you excite the impulsive and the emotional faculties, and this means you are weakening your power of concentration. You will not be a free engineer, able to pilot yourself to success.
Concentration of the mind can only be developed [...]

There is nothing that uses up nerve force so quickly as excitement. This is why an irritable person is never magnetic; he is never admired or loved; he does not develop those finer qualities that a real gentleman possesses. Anger, sarcasm and excitement weaken a person in this direction. The person that allows himself to [...]

The lower area of the brain is the store house of the energy. Most all persons have all the dynamic energy they need if they would concentrate it. They have the machine, but they must also have the engineer, or they will not go very far. The engineer is the self-regulating, directing power. The person [...]

Lesson II. The Self-Mastery: Self-Direction Power Of Concentration Part 5
When you shake hands with some one just think of your hand as containing hundreds of individual minds, each having an intelligence of its own. When you put this feeling into your hand shake it shows personality. When you shake hands in a listless way, [...]