Genius is the art of taking infinite pains.

The trouble with many Americans is that they seem to think they can put any sort of poor, slipshod, half-done work into their careers and get first-class products.

They do not realize that all great achievement has been characterized by extreme care, infinite painstaking, even to the minutest detail.

No youth can ever hope to accomplish much who does not have thoroughness and accuracy indelibly fixed in his life-habit.

Slipshodness, inaccuracy, the habit of half doing things, would ruin the career of a youth with a Napoleon's mind.
If we were to examine a list of the men who have left their mark on the world, we should find that, as a rule, it is not composed of those who were brilliant in youth, or who gave great promise at the outset of their careers, but rather of the plodding young men who, if they have not dazzled by their brilliancy, have had the power of a day's work in them, who could stay by a task until it was done, and well done; who have had grit, persistence, common sense, and honesty.
The thorough boys are the boys that are heard from, and usually from posts far higher up than those filled by the boys who were too "smart" to be thorough.