From Italo Calvino’s Six Memos for the New Millennium:

From its beginnings, my work as a writer has aimed to follow the lightning-fast course of mental circuits that capture and link points that are far apart in space and time. In my fondness for adventure stories and fairy tales, I have always sought something like an inner energy, a motion of the mind. I have focused on the image and on the motion that springs naturally from the image, knowing all the while that one cannot speak of a literary result until this stream of imagination becomes words. As for the writer of verse, so for the writer of prose: success is in the felicity of verbal expression, which can sometimes be achieved by a flash of inspiration but which normally entails a patient search for the mot juste, for the sentence in which no word can be replaced, for the most efficient and semantically dense arrangements of sounds and ideas. I am convinced that writing prose should be no different from writing poetry; both seek a mode of expression that is necessary, singular, dense, concise, and memorable.

Complement with John McPhee on writing as selection, my best advice for authors, and Granular verisimilitude.