Pick one distinct incident to write about. If it is linked to one or two others, you can include these, but don't wander in thought or direction.
Include dialogue and scene descriptions in your essay. Though describing a person is effective, you can often tell more about someone's character by their words. Most people think essays have to be exposition only--and that would be boring. You have leeway to entertain the reader as you write.
Be clear and concise in your writing. You can let your personality come across, but if you are a wanderer in thought by nature, try to keep it to a minimum in your story telling.
Tell the truth in your personal essay. Give the complete story, even if you aren't the hero/heroine. Always write the good, the bad AND the ugly. A reader will be endeared to you for being honest.
Proofread and edit the story after a few days. Once you have written the essay, walk away from it. This will give you distance and a better perspective to come back and revise the piece.
Have fun with your personal essay. If you are funny, be funny. If not, maybe you shouldn't try. If you're serious, be serious on paper. Don't try to change your personality to write about yourself. Your voice is your voice; write the story as you would speak the story.
Begin your personal essay with an intriguing or entertaining part of the story. Personal essays can be written out of chronological order. You can begin with the end, the middle or the beginning of your story. The goal is to draw the reader in with the most compelling part first.