Proofread
First, have an editor or someone with thorough command of semantics and syntax read over your narrative and correct any typographical or grammatical mistakes. This includes giving attention to diction, grammar, spelling, and mechanics. Simple proofreading is not about massaging content; it is about correct usage and presentation. It might also include spacing, fonts, and other formatting issues that effect how the manuscript looks on a printed page.
Edit for clarity
Reread the manuscript with an eye for clarity. This entails eliminating wordiness or confusing language. The more work that the writer does, the less work that the reader must do to comprehend the story. Writing a narrative in a clear, concise, forthright manner will make it not just more enjoyable but also more meaningful for readers. For example, the following sentences convey the same information but in different ways. The first sentence is wordy and the second sentence is concise.
"Although I had been bitten by a spider and had an unsightly bump on my face, I still faced the day and went to the photo shoot in the morning."
"Even with a big spider bite on my face, I had to show up at the photo shoot."
Show, Don't Tell
Describe events vividly rather than simply telling the reader what happened. For example, a "telling" sentence might read, "His bike was destroyed." A "showing" sentence might read, "The car crushed the bike frame and ripped off the wheels in an instant." It is clear which sentence is more descriptive. Using the active voice rather than the passive voice also more vividly "shows" a story's events.
Have others read your work and comment on it
Have a few different people read the narrative and offer their critiques or comments. It might be hard to take if they say anything negative, but ultimately their advice will help you revise. Consider all comments and make any adjustments to the narrative that you feel will enhance it. Perhaps some questions will arise that you could answer within the story to make it clearer, or perhaps some verbiage could be eliminated.