In order to succeed it is not necessary to be much cleverer than other people. All you have to do is be one day ahead of them.

Leó Szilárd (1898-1964) Hungarian-American physicist

“I’m looking for a market for wisdom: Leo Szilard, scientist,” LIFE‎ (1 Sep 1961)

Variant: "If you want to succeed in the world, you don't have to be much cleverer than other people. You just have to be one day earlier."