A good writer is a good communicator, which requires an eye for detail and a knowledge of what is being described.
"Everyone was plainly already asleep, and it was some time before an aged porter emerged from the depths of the house. He was so doubled over that he cannot have been able to see more than the lower half of anyone standing in front of him. Because of this handicap, no doubt, he had already taken a quick glance at the latecomer outside the glazed door before he crossed the hall, a glance that was the more penetrating for being brief."
"Just as the winter days I had spent in America three years before had been dark and colourless, so now the earth's surface, a patchwork of greens, was flooded with light. In the long since abandoned pastures stretching towards the mountains grew clumps of oaks and alders; rectilinear plantations of spruces alternated with irregular stands of birches and aspens, the countless trembling leaves of which had opened only a week or so before; and even on the dark, distant slopes, where pine forests covered the mountainsides, the pale green of larches lit by the evening sun gleamed here and there in the background."