Once I have feedback from all my various sources, it’s time to assess the book.
I try address every problem I heard from more than one source. So if someone in my writing group mentions a problem, and others chime in (oh! I had that problem too!) then I make the change. If I heard a comment from one beta reader and also from my agent. I find a way to address it. In addition I make all the changes that I heard from only one source, but that I agree with myself.
Here’s the thing: every reader is right. If your critiquer says your book has a problem, there is a percentage of your readership who will also have this problem. There’s no point in arguing with them. They are right about their experience, and if one person feels this way, others will, too.
But there’s no way to please all readers. So I try to make all the changes that bother larger percentages of my test group, plus any changes I just like. And I let the outliers go, knowing that means I will alienate a few readers.
Here’s the truth, though: I mostly hear iterations of the same problem from everyone. Readers will describe things differently, but usually they’re all getting at the same underlying issues in the book. It helps to hear about these problems many times, because each critiquer will have a different perspective, which will give me different ideas of how to fix problems.
But at this stage, I’m not fixing. I’m just assessing. I usually open a fresh word document and write down the nature of all the big things I need fixing. I make a list of all the massive changes, the medium (chapter or scene size) changes, and then the line changes. Sometimes I print out the manuscript and mark it up, reading it over fresh. Sometimes I cover that printed manuscript with post-its. Sometimes I re-outline, and sometimes I just make myself some digital notes in a separate file, and keep that open as I work.
But once I’ve compiled my list of changes, it will be clear to me what size of a fix is needed: a rewrite, a heavy revision, a light revision. I’ll wrap my mind around the work at hand, and then I’ll get to it.