Ah the thing that we overthink sometimes to the point of madness. It's meant to capture the attention of your reader, or soon to be reader, in just a few sentences. And it should be 'like, totally you right?' Hmm. Yes, but what exactly makes a good bio?
There is no perfect formula. Sorry to disappoint you. But here are some tips:
Simple as adding in that you like coffee or scary movies. That you sing in the shower. (ok maybe not that) but something that makes the reader see you as just another person like them. Not some unreachable author who wants you to buy his/her book.
I think humor goes a long way and I love it when my favorite authors add some in their bios. Makes me smile and...well, it makes me like them even more. Now, if you're writing more serious stuff, or perhaps non fiction--that's probably not the way to go. But otherwise I think it works perfect with almost any genre.
Where are you from? You don't have to give your street address (probably not the best idea anyway) but even mentioning the state your in can give the reader a, "Oh! I live there!" or "I've been there before!"
Yup. It sounds too easy. That's because it is. It's YOUR bio. It's about YOU. So let that shine through! Give them a little taste of your author voice, as well.