The Perils of Pre-order

First, the upside of arranging pre-orders of an upcoming book. If an author sets a book up for pre-order, the sales that come before the release date count as sales on that day, which raises the book higher in rankings, which shows it to more people, which in turn generates more sales.
In theory, anyway.
I'm not much for figuring out the ins and outs of selling more books. I'd rather write more.
The downside of pre-orders is my anxiety level. I have to cross-my-heart-and-hope-to-die promise I'll get the book done by June 20, ten days before the "official" release date so Amazon knows I'm trustworthy. If I fail, they promise to never let me pre-order again (well, for a year, anyway).
I could live with that, but I hate failing, so I won't if I can possibly help it.
The problem is I'm waiting for others to do their jobs and hoping that their jobs (editing) won't require too much more work from me (re-writing/fixing errors).
When I signed a contract for my first book, the release date was two years away, and I wondered, "What takes two years?" and "What will I do in the meantime?"
Today it doesn't take that long, although big publishers have a queue and you get put into it somewhere at least a year from the date of signing. Still, it takes more time than authors would like to get decent editing, a good cover, and proper formatting. I know people who think they can do all that next weekend after the softball game but--ahem--they're wrong.
As for what authors do "in the meantime"? Work on the next book, of course, which is what I'm going to do as soon as I post this!