Describe people, places and events in with in-depth detail. Bring your subjects to life with descriptions of how they look and dress or their facial features as they react to a situation. Explain every facet of an environment, including plants, animals and weather conditions.
Set the stage for the story with background that help the reader understand the history that led up to the reason for the story. Provide deeper insight into all the pieces that went into the thoughts and actions of your characters.
Use flashbacks to explain the details of the present story. Put stories within the story to add depth and details and make writing longer more fulfilling. You won't be accused of padding the prose with unnecessary verbiage.
Write an outline before you begin the actual story-telling. Often you can come up with more ideas and areas that you want to cover in your work when you think about it terms of bullet points and separate ideas. Brainstorm and write down everything you want to include.