Years ago, Kurt Vonnegut wrote an article sponsored by the International Paper Company, on how to write with style. He intended it mainly for writers of non-fiction, but the tips apply equally to novelists or short story writers. I'm featuring one per day; this is number eight, the final one. The sketch is his self-portrait.
For really detailed advice...
For a discussion of literary style in a narrower sense, I commend to your attention The Elements of Style, by William Strunk, Jr. and E. B. White. E. B. White is, of course, one of the most admired literary stylists this country has so far produced.
You should realize, too, of course, that no one would care how well or badly Mr. White expressed himself, if he did not have perfectly enchanting things to say.