Think of your life as though you were someone else and not yourself. This will help in enabling you to more easily write your biography in the third person and will bring to mind the more interesting aspects of yourself that you will want to include.
Decide on a few aspects of your life you want to write about in the biography. Focus on including anything that is relevant to your career, education and another areas of your life that gives readers insight into your personality, such as a hobby.
Write a few short paragraphs to keep your biography succinct and to the point. Use your full name in the first sentence, and refer to yourself by just your first name or as "he" or "she" in the sentences that follow.
Proofread your biography. Edit any mistakes you notice, and rewrite any awkward sentences to make them better. Use the spell-checking function on your word processing program as well. Have another person look over your biography so that fresh eyes can proofread it.