Many writers lament about how hard it is for them to write their own author bio. It doesn’t go as quickly as we think and their optimum message is harder to craft. It’s best to have our author bios written before we need them. And even if our pre-written bios don’t provide the right slant or hit the target length, it’s easier to tweak what we have already written to match what’s needed, then to start with a blank screen.
Write your author bio in the third person, except for a query letter or proposal, when the first person is used. There are four typical bio lengths and our goal is to have all four:
25-Word Author Bio
A 25-word bio is ideal for articles and guest blog posts. It’s usually two to three sentences and contains basic relevant information about you as an author: who you are and your credentials, plus a plug for your book, project, or blog.
50-Word Author Bio
A 50-word bio is also ideal for articles and guest blog posts, as well as blog sidebars. If you’re not sure which one to use, submit the 50-word version (or ask or submit both). The 50-word bio contains the same information of a 25-word bio, but more of it. (Some authors write a 75 to 100-word bio instead of a 50-word bio.)
Many authors include an intriguing, playful, or memorable line – especially in their 50-word bio.
A 25 or 50-word bio will be ideal for an article, query letter, and one-sheet. Look at the bios found at the end of magazine articles for more examples and ideas.
250-Word Author Bio
A 250-word bio fits on the back cover of most books; it is also appropriate for your media kit and an “About” page on your blog or website. Start with your 50-word bio and expand it, adding meat and items of interest that relate to your writing and specifically to your book.
500-Word Author Bio
A 500-word bio may fit on the inside flap of your book; it’s also appropriate for a media kit and an “About” page on a blog or website. Build upon your 250-word bio, adding more substance and human-interest elements.
A 250 or 500-word bio will go in your book proposal, as well as for a book and website’s About section. Look at book covers for more examples and ideas.
For more info: http://buildbookbuzz.com/how-to-write-an-author-bio/