Write an outline of the information you want to include in your bio. This is a good time to decide on tone and approach. Decide if you want to include strictly professional information, such as your publishing highlights and any awards you've won, or if you will also include something personal. Consider the tone of what you will write. If you're a horror writer, you may want to put a horror slant on your bio.
Aim for between 200 and 250 words for your bio. Open the first paragraph with your name. Write in the third person. The opening paragraph should contain professional information. It might go something like this: "Joe Writer is the author of 23 books on paranormal activity, including the New York Times bestseller Ghosts Walk Among Us..." Follow this up by mentioning a couple of additional books readers may be familiar with. Take advantage of your bio to highlight some of your lesser known books as well, which can help boost sales.
Include any awards you've won and whether or not you are a member of any writing associations. If you're involved in any special activities related to writing, include them in the professional segment of your bio.
Reserve personal information for the end of the bio and keep it to a minimum. Personal information might include where you grew up, the state where you currently live and any interests you have outside of writing. Personal information might look something like this: "Joe Writer grew up in a small town in Indiana, where he still resides, along with his two Dobermans, wife and five kids. In his spare time, Joe enjoys biking and hiking."