This question came up on one of my writing loops, so I'm shamelessly stealing it for this blog post.
How many completed manuscripts should you have under your belt before you query? 2? 5? 20?
How polished should those manuscripts be?
And what about series ideas and sequels and prequels?
The more I talk to agents and editors, the more I realize that they want to hear lots of IDEAS. Polish of the manuscript can come later, but if they don't like your first pitched idea, it doesn't matter that the book finaled in contests and is polished to a high pitch. You better have another idea to pitch to them if they say no to the first pitched idea.
This is what happened with my Sushi series. The pub board hated the first book idea (an old version of Trish's story), but they wanted to see the second book idea/manuscript (Lex's story in Sushi for One).
I have several writer friends who have between 5 and 10 finished manuscripts. Don't freak out, many of them have been writing for years.
When I sold my first novel, it was actually my FIFTH completed manuscript. Most writers say the same thing—they completed several manuscripts before selling one of their latest ones.
The point is that most of those manuscripts in their inventory are not polished, but those manuscripts each have a unique story idea.
If an editor/agent doesn't like one idea, the writer has another idea/manuscript to pitch.
Those ideas don't include sequels. Most of those 5-10 finished manuscripts are either stand alone or the first book in a series, with the 2nd and 3rd books roughly outlined but not completed.
Because there's always the chance that the editor/agent won't like the entire series idea/premise. If all your completed manuscripts are in the same series, you're up a creek when an editor/agent asks you if you have any other story ideas!
I'm not saying you shouldn't pitch to or query editors/agents when you only have one or two completed manuscripts. You never know!
I'm also not saying you shouldn't polish your completed manuscripts. Definitely polish them—but don't spend ALL YOUR TIME polishing the same manuscript or two. Go on and write other manuscripts! If the first ones aren't absolutely perfect, don't sweat it. As long as they're readable, they're fine.
What's more important is that you have new and different story ideas in your inventory.