I've got draft versions of all the chapters of the book-in-progress now, which is great. Of course, when you add up all the words in those chapters, it comes to 92,000, when the contract calls for 70,000. Which means I've entered the part of the writing process where progress is measured not by how many new words I type, but how many old ones I can make disappear.
I always find this faintly depressing, but it's a nearly inevitable part of serious writing for me. There have been a few cases where I've had open-ended writing assignments-- one of the papers I published in grad school, and my Ph.D. thesis itself-- but for the most part, my professional output has been length limited. As a student and a post-doc, I always needed to edit words out to fit the length limits (4 pages for Physical Review Letters and about the same for Science). As a faculty member, I've needed to meet page limits for grant applications, op-ed articles, and now books.
This is another area where I always have trouble getting my head around the usual student mentality. Most students complain at length about minimum length requirements, wondering how they'll ever stretch their thin argument into the required ten pages, or whatever. Even when I was an undergrad myself, though, I never really understood this-- adding more words has never been a problem. Give me a minimum length limit, and I can exceed it by 30% without breaking a sweat.
If you want to see me squirm, give me a maximum length requirement. Because I can exceed that by 30% without breaking a sweat, too, and almost inevitably will. The sweat (and tears, and occasional blood) comes when I have to cut the text down to meet the target.
In that case you've probably heard this quote before:
Perfection is achieved, not when there is nothing more to add, but when there is nothing left to take away.
- Antoine de Saint-Exupery
(Oh, and I finally bought your first book this past weekend! Yay!)
To follow up one translated French quote with another:
"I have made this letter longer than usual, because I lack the time to make it short" - Pascal
So how do you edit down your manuscripts? Is it just a constant matter of re-reading and editing or do you have some specific process?
It sounds like you need more of a range rather than some minimum or maximum. Perhaps a 95% confidence interval for total number of words is in order...
And you think you've got problems? The first draft of the book I've recently delivered to its publishers came to ~250,000 words, as against a target of 100,000.
92000 - 70000 = 22000, which is c.23% of your text. So just eliminate _____ fourth word and _______ solved.