That is the title of a 1989 article in Sociological Theory by Daniel Chambliss (which I found through this blog post titled “Does one have to be a genius to do maths?” written by the famous mathematician Terence Tao).
The paper is excellent and inspiring. Chambliss follows swimmers of various levels and finds that what sets Olympic-caliber swimmers apart is not that they do more of something, but that they concentrate on very small and very specific parts of their swim over months and often years. They don’t swim, say, two times longer than club-level swimmers, but instead might spend several months concentrating on the mechanics of a flip-turn and all its components, whereas a lower level swimmer may focus only passingly on the flip turn, or not focus enough on all its individual elements. The paper has many examples both in swimming and in other endeavors.
The paper concludes with this:
…there is no secret; there is only the doing of all those little things, each one done correctly, time and again, until excellence in every detail becomes a firmly ingrained habit, an ordinary part of one’s everyday life.
See also this Michael Phelps commercial: