I started by skimming through the novel and making a chapter by chapter outline, just noting the major event(s) of each chapter. This is something I do almost every time I revise (unless the outline from the last draft is still accurate) because it lets me see the structure of the story quickly, and it makes it easier for me to consider where I might add events or character development or whathaveyou.
Then I read over the comments I'd gotten from my critique partners, and made a document where I wrote down everything I thought I'd want to keep in mind for the revision. Mostly general thoughts but also a few chapter specific things.
When I was done that, what I mostly had was a big mess. (Four pages of scattered notes.) So I made another document, where I organized the notes into categories: questions to answer, elements that could be expanded, major areas to work on, prose-level concerns, and the chapter by chapter stuff. It's still four pages long, but at least it's more focused now.
Over the next few weeks (or more, depending on what comes up after I get back from Italy), I'm going to be looking over those notes and considering how I might answer the questions, and where I might add more about certain elements, and how I can address the other major concerns critiquers had. And then, naturally, I will rewrite! :) Though probably I will re-outline, first, so I have an outline that reflects the structural changes I decide to make.
Something I suppose I've always had a sense of, but really noticed while thinking about this revision, is I make many of the major decisions about how to tell a story based on what feels "right", rather than any practical reason or creative theory. For ex, as I was reading over certain passages of the book, I started wondering how it might sound in first person, like GutG and PL. I remembered reading posts of writers discussing why to use one or the other, and what effects POV has on the story. I wondered if maybe I should look those up and analyze the situation based on them. And then I tried to imagine the first scene of the book in first person--and it just felt wrong.
Okay! I thought. The story has spoken. Third person it is.
Sometimes I feel like I should be a little more analytical about things like that. Or at least be able to articulate why one thing feels right and the other wrong. And maybe I could, if I really pushed myself to pick it apart. But those analytical reasons are not why I made the decision--the feeling is.
Thankfully, my gut generally seems to know what it's talking about, even if I don't. ;)