Philosopher Richard Wollheim knew — learned — how to pay attention:
I evolved a way of looking at paintings which was massively time-consuming and deeply rewarding. For I came to recognize that it often took the first hour or so in front of a painting for stray associations or motivated misperceptions to settle down, and it was only then, with the same amount of time or more spent looking at it, that the picture could be relied upon to disclose itself as it was.A related post
I noticed that I became an object of suspicion to passers-by, and so did the picture that I was looking at.
From Painting as an Art: The A. W. Mellon Lectures in the Fine Arts (1987), a series talks given at the National Gallery of Art in Washington, D.C., in 1984.
Joe Brainard on looking at art