A personal narrative needs to have a point or hold some kind of significance. This doesn't mean you should just stick a trite moral onto the end of your story. Try to think back to an event that changed you, or where you learned something. If the experience really held significance for you, it should be natural to weave this into your narrative and it will really shine through as a subtle nuance in your finished piece.
Although your personal narrative is a nonfiction piece, you're still telling a story. As such, you need to have a linear plot with a clear beginning, middle and end. The plot should normally contain a conflict or a point of tension and a resolution of this conflict. This resolution often leads to change, whether that change is in yourself, in another character or in the circumstances or events surrounding your narrative.
A personal narrative is written in the first person, so it should be from your perspective and about you. Essentially you are the main character, so try to give the reader a good idea of the person you are, through your actions, voice and awareness. However, you still need to have other characters in your narrative. Your characters should be interesting and believable. Try to work on your characters' dialogue, to make it lively and realistic.
The setting is important in your personal narrative. Try to make the story come alive by describing it in detail. Think back to the place you're writing about and include details about what you saw, heard and smelled, and how you felt. As well as the physical setting, you need to think about the place it took up in time. Let the reader know when it took place and give a clear sense of the passage of time.