Writing improves our thought process and communication skills. It helps the writer keep his imagination going, and come up with interesting ideas and stories.
There is a huge difference between telling a story verbally, and writing a story, or a narrative essay. An essay may be a reflection of the author's views and personal values, molded in the form of a story. However, there are some tips that are to be kept in mind.
Before you start writing, just relax for a moment, collect your thoughts, and try to write steadily. Use clear and simple language that would be easy for the reader to understand.
Ensure that the main story is introduced in such a way that would distinctly indicate if it is a personal experience or just an observation. You may start the introduction with a quote or a proverb if you want.
If you want to write about an experience, understand why it was important. Try and sort out the recollections of the experience, and create an outline based on it. You can certainly structure the essay in a better way using the outline.
You may also use dialogs is some cases, but largely try and avoid their use. Write an essay that seems realistic. Mention sensory details that would attract the reader's attention.
Try to inject some humor to help lighten the mood.
Build your essay around a central theme, and build around the point to provide clarity to the readers. Don't switch ideas often, or switch between conclusions, as it may confuse the reader.
Put yourself in the shoes of the main characters, so as to elucidate on your thoughts. Put an 'I' in the place of the protagonist of the story, and start writing. Don't bother about the number of times 'I' appears in the essay, or how much unfocused and unordered the points are. Write whatever you feel is correct. This is known as freewheeling essay writing. When you've finished writing or have written the concluding paragraph, read the essay all over again and try to put all points into their correct place, and replace the pronouns if needed. If it is an essay of your own experiences, you need to keep the 'I'.
After you have gone through the essay thoroughly, and have eliminated all the possible errors, spend some time away from it. This should give your mind a break, which is necessary to find mistakes which may go unnoticed if you read the essay immediately after you write it. If you are still not satisfied with it, get a second opinion. The neutral criticism may be tough to accept, but it will help you improve better than even the harshest evaluation you can do of your own work.
Scan the essay and ponder over the details. Try and remove redundancy and any minute mistakes. Conclude the essay properly and logically, tying up any remaining loose ends.
Do the best you can! Good luck!