Go out and find bios of successful people and take them apart, examining the individual elements to discover what works and why it works. You are going to be building your 'brand' with this bio, so follow the example of the experts in creating your own set of bios. Yes, I said, 'set' of bios, because you will probably need more than one, depending on the purpose of the bio, the audience you are appealing to, and the 'product' you are offering.
Tell the reader immediately what it is you do. Don't just start out with something like "Janie Sullivan is a writer." Big deal, so are hundreds and hundreds of people. Identify your niche, "Janie Sullivan is a leading expert in faculty training curriculum development." This immediately tells the audience that I know what I am talking about in the area of faculty development curriculum, a very specific area of writing. This also shows that more than one bio is necessary, not all the 'audiences' I serve are interested in faculty development.
Provide evidence that the first statement is true in the following, or even included in the first sentence. In this case, I would follow up with "She has written the entire curriculum for a 21-course online certificate in Online Teaching Strategies and currently teaches this curriculum online at a local community college." This establishes credibility by showing I have experience in curriculum writing and it identifies my audience. If you are a faculty member wanting to learn about online teaching strategies, you will continue reading my bio.
Give more examples showing what you have done in your area of expertise that set you aside from others doing the same thing. To continue with the example above, the next sentence would be "Janie has written articles in the art of online teaching for the Adjunct Advocate, a magazine devoted to adjunct college teachers. She has also presented training workshops on related topics at the Innovations in Community Colleges Conference and the Maricopa Community College Tech Conference."
Include your email, blog and/or wiki addresses, if you have them. If not, include a phone number where you can be reached. If you do not have a Web site, now might be a good time to set one up. It can be a simple blog or wiki, or an elaborate site that provides your audience with a more complete picture of who you are and what you do.