Make sure there's surprise in your story. Strive to make sure the surprise is fresh and stands out from other people's stories. Reality beats steady in the detail of fiction. But surprise is what makes the reader sit up and take notice. Nothing should happen at random.
Plot stems from character under adversity.
Each character has an urgent personal agenda. The plot is the synthesis of the plots of its individual characters. The plot begins long before the story. Foreshadow all important elements. Keep in mind the story you're telling.