First, let's all take a deep breath.
Chances are, your book is not wrecked. It just feels that way because you can't make that scene work, or character turn into someone you don't expect, or the setting falls apart. There are a lot of different things that can skew and go off kilter in a book that will make you feel like you're doomed and you should just become a snake milker.
But it is possible to have a first draft veer so off course that it becomes "wrecked". By "wrecked" I mean this draft is nigh unsalavagable, or there's so much wrong with the plot, characters, and setting it becomes impossible to move on with the story. You did something so badly wrong this book has turned into something you didn't mean to write, and is nothing like what you wanted.
Now, sometimes you think you're writing about an action hero, and you throw in a secondary sidekick for him, but by the middle of the book you're more interested in the sidekick. There's nothing wrong with that. Books are different on paper then they are in your head. That's a normal part of the process.
And almost every writer I know gets middle draft blues. We've talked about why before, and the importance of continuing on. But what if you continue on with the book, like a good writer, and it still sucks? The writing never gets better, and you never feel the joy of creation you felt at the beginning?
Only you can know the warning signs to your book being wrecked--it's slightly different for everyone--but it would be wise to pay attention to these signs if they persist. Because sometimes you have to stop and take assessment of your book, and ask yourself some hard questions.
*Do I hate my main character and want him/her to die?
*Do I hate my plot, and think it's the most trite piece of crap ever?
*Do I have such big holes and leaps of logic in the plot I could drive a tractor trailer through them?
*Does my book smell vaguely of anchovies? (don't ask)
If you answered yes to any of these questions, on a consistent basis (remember, we went through the last post to clear up any middle draft snags you might experience. So this is assuming you've already done all of those little exercises) you might need to stop and think some Hard Thoughts about the book.
Your book might be wrecked. It might not be though. If you're under a lot of stress, good or bad, if life has just thrown some curve balls at you, if you're just tired in general, all of this can make you feel like your book is wrecked.
The time to assess your book's viability isn't late at night after a bender and crying fit. You want to be alert, relatively sane, and in good health. I suggest walking away from the book for a day or two. Look at the book carefully, and figure out what's wrong with it.
Sounds harder than it is. Hopefully with time away the culprit will jump out at you. The secondary characters took over the main plot, and that doesn't add to the story. You changed the tone of the book. You started a tangent that's taken over the entire novel. Something isn't working, and it's your job to figure out what.
Next, figure out what is still working. Main character still intact? Stretch of scenes that work really well to advance the plot? Make a note of that.
Figure out where you went wrong. Don't be like me, start over, and hit another problem 10,000 words in. In order to keep yourself from having similar problems you need to figure out what went wrong, and how you're going to fix it. If your secondary characters took over, make a note "Bob, Jim, and Sally are all spotlight hogs. Why did I let them take over?" Were you bored with the main character? Did you just not know what to do in that scene so they took advantage of your weakness?
Go through the book and make a note of each problem you find. Write a solution to each problem. If you don't know what's wrong, you can't fix it. If you haven't figured out now how to fix the problems, you won't be any better off when you start over.
Now comes more decisions. How much of your book is salvageable? If a good chunk of it is still worth keeping, I would set that aside. Start your book over, and work in the salvaged stuff as you can. If most of it isn't worth keeping, just start over.
I know. It's hard, but sometimes it's necessary. This is the most drastic step to take. Most of the time you won't have to start over. Most of the time, you can make some fixes and push on. But sometimes you need to start over. Make sure you're not being too hasty and keep your chin up.
Also, take this advice with a hefty grain of salt. Writers have a wide and various process for writing, that even changes from book to book. Listen to your instincts and don't be hasty. I am by no means an expert. I am just trying to pass along some stuff I have figured out the hard way.
How do you know when a book isn't working? What do you do when that happens?