Somerset Maugham once said, according to some sources, “There are three rules for the writing of novels.Unfortunately, nobody knows what they are.” He was playing to our desire for learning the secret ingredients we're sure the best writers and bestselling writers have found. He was also following his claim with the reality of our situation: there are no three rules that we can follow even if we follow them.
Just so we're clear. I've got no rules to give you but I do have an approach that works for me and that I've developed over time and that might just work for you. It's simple. That is it has a simple version.
Use both sides of your brain.
One side you should use for story, plot, character at the plot level (interaction of character and story), setting, and pacing. This side tells a good story.
On the other side: this side should be used for language—making sentences that use language in a way that pulls the reader into your story. Create powerful descriptions and detail that comes from seeing scenes as a camera might see them. Creating real characters that readers believe in. Finding just the right tone for the story. The use of dialogue for both plot and character development. This side is about using language in such a way that the story emotionally engages the reader or engages him/her in other ways: makes the reader laugh, think, whatever.
The two sides overlap, of course, but here's the kicker: You need to use them separately. You need to be able to create a good story AND use language as a way of connecting with your reader and giving depth to your story but you can't do them at the same time or at least not at first. You need to think of them separately until you can use them together without thinking. Even then I'd say you need, in revision, to isolate and work on both sides since both are essential to writing fiction.