I only speak from many years of making mistakes. First, we usually think our manuscript is more ready for prime time than it is. I've sent mine out too early, in a rush of "I'm sick of working on this" or enthusiasm from recent writers' group feedback, with bad results. I lost the goodwill of an agent I was courting. I turned off at least one publisher. The war wounds were hard to recover from. So my advice, however hard to hear, is take your time.
An experienced author once told me: "You want to be proud of this book ten years down the road, after it has been published. You don't want to pick up a dusty copy and cringe."
I followed his advice with my last three books (takes me a while to learn) and they are still in print, and I am still proud of them.
So when do you know? When is it really time to hit the streets with your hope?
1. Hire an editor. When you've done as much as you can, when you're cross-eyed with reading the manuscript yet again, shell out some money to be sure. Editors are not cheap but they are happy additions to the process. Two great resources: Grub Street writing school in Boston and The Loft Literary Center in Minneapolis. Both have listings of faculty who hire out as manuscript readers. Find out their terms, test them with one sample chapter, see how the exchange feels to you. Are their comments useful, encouraging, giving you the next step? Or do you feel deflated and ready to ditch the project?
2. Spend time with the editorial comments. I often take the hired editor's comments back to my writers' group or a writing partner to discuss. Then I make a to-do list--and ask the editor for clarification if I cannot get a clear next step from the suggestions. For instance, "This character is not quite coming alive on the page for me" translates to what? What next step would you take? If you're not sure, you'll stall out. Discuss with your buddies, email the editor for ideas. Get something solid to step on so you don't flounder.
3. Go through your revision checklist again, after you've made the changes. Remember that small changes in one chapter will ripple into others. Pages added mean page references (in appendix, table of contents) are changed too. Click here and here for past blog posts about my revision checklist. Very important is the step of printing it out and looking for balance of white space and text (point #2 on the checklist). Mark the changes on the printed manuscript this time, not in your computer--hold off on that step.
4. With the same printed, marked-up manuscript, do an outloud read-through. This is my most important tool. After I've marked the new changes, gone through the revision checklist, and feel the changes I will make are solid, I read it aloud. To myself. Or to a tape recorder. I use a yellow highlighter to mark ANY moment when I stumble, have to reread, feel something is missing, or hit an awkward passage/word/chapter. I try not to be too frustrated by this--there is bound to be stuff I find, and I just have to accept that's the nature of the book writing process. We miss our own mistakes. This catches 99 percent of mine, usually.
5. One more round. Make a to-do list again of the places that need more attention. Do the work. Go through the revision checklist, read aloud once more. The goal is to have it sail along completely smoothly when read out loud--the big test!
6. Now find your beta readers. These long-suffering friends are exchange partners--you do it for their books, they do it for yours. Write a list of questions you want them to focus on. Give them time to read and respond (I usually ask for 6-8 weeks turnaround, but that's not possible sometimes, so do your best). Be sure to write their names down in a safe place for (1) mention in your book's acknowledgements page and (2) a thank-you copy of the printed version after publication.
7. When you get feedback from the beta readers, start with step 2 again. This may send you running and screaming, but you're almost done! Often, after this much work, the manuscript is very close to being ready.
8. When it passes the final read-through out loud, it's done. Ship it off! And take yourself out for a celebration (or sleep for a week). You've earned it.