(NOTE: This is specifically for fiction queries. In non-fiction queries, the bio paragraph is a lot more important).
RULE #1: If you're not sure what to write about yourself, write:
Thank you for your time and consideration.And NOTHING ELSE. Seriously. The agent is interested in your story. Nothing you write here will change their mind about that.
The bio paragraph is frosting. Yes, frosting can be very pretty and tasty, but if the cake sucks, the agent isn't going to eat it. Conversely, if the cake is awesome, but the frosting is . . . weird, the agent MIGHT scrape the frosting off. Or they might decide to go with one of the other equally awesome cakes topped with plain vanilla. Which brings us to . . .
RULE #2: You are not a special snowflake.
I mean, you are. Of course, you are. But so are the other tens of thousands of writers who want their book published (that's why they call it slush, cuz, you know . . . all the snowflakes).
And you know what? All of them were born with a pencil in their hands too. Or were published in local writer's journals. Or have a critique group. Or head the local chapter of SCBWI. Or came up with the idea when they traveled to Ireland. Or were inspired by God.
Whatever.
None of these things mark you out as special. For agents who have seen them over and over, they mark you out as someone who doesn't realize how not-special they are. And since you can't know what they've seen over and over, see, Rule #1.
RULE #3: Include professional publishing credits only.
"Professional" means you were paid professional rates for it, typically 5 cents/word and up. If all you got was half-a-penny per word and a copy of the magazine, chances are the agent hasn't heard of the publication. And if the agent hasn't heard of it before they read your letter, they're not going to care when they do.
RULE #4: Include previously self-published books if you sold more than 20,000 copies.
Less than that isn't as important as you'd think.
RULE #5: Mention if you share some background relevant to the story.
Like you have a degree in whatever skill the protagonist uses to solve his problems, or you live in whatever exotic location it's set in (Canada? Not so exotic. The Ozarks? Surprisingly, yes).
RULE #6: You can include something unique about yourself. I guess.
I don't want to tell people not to include stuff like this -- it's memorable and unique, and I've seen it done in cute, writerly ways that made me laugh.
But you won't ever look bad if you follow Rule #1. I mean, what could be more unique than living in Thailand and raising 10 kids? But I didn't say any of that in my query, and it didn't hurt my request rate any. In the bio paragraph, less is more.
What do you think? Agree? Disagree? Tell us in the comments.