Okay, I just finished my rough draft of my first cozy mystery for Heartsong Presents Mysteries. It's just over 62,000 words (the assignment is 62,000-63,000 words, because they have such a specific trade size for these books). I've actually been editing as I go, otherwise the manuscript would have been much bigger.
So I made a printout, burned a copy on CD, and put it all in a box. In two or three weeks, I can come back with fresh eyes and start finessing it -- trimming some parts, expanding others, making sure all the moving parts work correctly. After that draft, I'll start sharing it with my early readers, who will poke holes in it, helping me see any structural or continuity problems. (You'd be surprised the things an author can miss because he or she is too close to the work.)
Then another revision or two (or five) and off to my editor.
During this whole process, by the way, I'll be working on other things: outlining books #2 and #3 for this particular series; working on a pitch for another series entirely; and writing some short mysteries. I also plan to have the rough draft of #2 written by the time I get #1 back for revisions. (I've got to have all three done by February, so it's important to pace myself.)
Here's a tip: Your editorial deadline is NOT when you need to have your first draft finished. You have to build in time for two, three, four revisions before you send it to your editor.
So that's my plan.