Even back in my 35mm days, I tried to think of photography different than "snapshots"... but what is the mind-set for taking photos in that way? How does a photographer think different about composing the light, the geometry before clicking the shutter?
One of the masters of photography going back to the 1930's was Henri Cartier-Bresson, and in 1973 he was interviewed on his style and methods, which is the basis of the video I have linked to below. He was first an artist (sketches, etc.) and then took up photography, which he describes as an "instant sketch", and his artistry shows.
Watch the video and not only here from Mr. Cartier-Bresson himself, but watch a menagerie of his brilliant and beautiful photos as he talks about his art.
"Photography is like 'Yes, yes, yes!', and there are no maybes, or the maybes should go to the trash. It's very instant, it's a presence, its an affirmation of the moment."
Video: "The Decisive Moment" (c) 1973, 2007 International Center of Photography
Amazon link to the many books and biographies.