Essays are short pieces of writing, usually confined to one specific topic or idea, otherwise known as a thesis. Choose a topic that has special meaning to you. Use prompts around significant experiences in your life, such as an event that changed your life in a very specific way. Don't be afraid to tackle a topic you are passionate about because this conveys emotion to your audience. Talk about a failure, or learning from a bad deed. Whatever it is, make it one specific idea.
As a first-person narrative, the temptation may be strong to meander in the details. For an effective essay, you should aim to be concise and not muddle your main topic. For instance if you opt to talk about the importance of friendship between siblings, pick one specific story from your childhood to illustrate this point. Decide which cast of characters will support your main idea and keep it limited to only the information needed.
Because a narrative works like a story, all the elements of story must be present. One of the better ways to achieve this strong spine to your essay is through an outline. The beginning establishes your main idea, whereas the middle will illustrate this idea through a specific event. This event should have a climax that will segue into the conclusion, which brings the reader's insight into your main idea.
A narrative essay pulls the reader into the writer's particular world. Use this creative license to paint a specific picture with your words. Use concrete language rather than describing things in the abstract. Let them see the house you grew up in by the words you choose, or feel that awkwardness or isolation by emotion you evoke on the page. Draw the reader in and let them see through your eyes.