From The Lancet:

Hard work is required: “Genius is one per cent inspiration, ninety-nine per cent perspiration” - Thomas Edison

Late in life, Charles Darwin made the same point in a letter to his son: “I have been speculating last night what makes a man a discoverer of undiscovered things, and a most perplexing problem it is.—Many men who are very clever,—much cleverer than the discoverers—never originate anything. As far as I can conjecture, the art consists in habitually searching for causes or meaning of everything which occurs.” Darwin was a relentless student of nature from 1828 until the few weeks in late 1838 when he suddenly perceived the mechanism of evolution by natural selection.

There can be no doubt that geniuses have worked habitually and continually. Darwin produced 160 published papers, in addition to celebrated books and a vast correspondence. Albert Einstein had 240 publications, Sigmund Freud 330, Henri Poincaré 500 papers and 30 books; Edison was the owner of 1093 patents, lodging an average of one patent every 2 weeks of his adult life. In the arts, J S Bach on average composed 20 pages of finished music per day, while Pablo Picasso created more than 20,000 works.

Experience is essential: “Where observation is concerned, chance favours only the prepared mind” - Louis Pasteur

The 10-year rule states that a person must persevere with learning and practising a craft or discipline for about 10 years before he or she can make a breakthrough. The initial scientific evidence for the rule came from studies in the 1960s and 1970s of chess-players, who take 10 years and more to become masters of the game. Then it was found to apply to Olympic swimmers and concert pianists.

Hardly any genius in history—not even Leonardo da Vinci—seems to have short-cut the long and gradual path to creative breakthroughs.

References

Perspiration, inspiration, and the 10-year rule. The Lancet, Volume 376, Issue 9751, Pages 1458 - 1459, 30 October 2010.

Twitter comments:

@equijada: the ability to infer disparate ideas into one is the 1%. The rest is just salty water. 10-yrs, 10,000 hrs -> playing w/ observations