I don’t have any experience, or a lot of advice on author bio’s, but I think something that I find appeals to me is someone who is straight-forward, funny, and informative.
You’re talking about a real, true human being (yourself), so make it sound like that. Be relatable to other people…so that readers not only feel that they can connect with your characters, but you as an author. Writing it in a similar style that you do in your stories might also be a subtle bonus (or eluding to characters and quotes from your book).
And especially, make yourself feel available. Tell them they can send you fan-mail or ask you questions. I can’t think of many things more rewarding to a reader than being able to connect with an author and share their enthusiasm about the story (especially if you reply to them😄).
I personally don’t really take into account how many other books an author has written (or how many they brag they’ve written), as long as I like the story. After all, Andrew Peterson hadn’t ever written any novels before the Wingfeather Saga, but that doesn’t change the fact that we love his books.
I think the main goal is to be authentic and open.