So, using the official NaNoWriMo etymology, January and February are the "Now What?" months. This, however, is where the official site falls short. Per their page on revisions, they recommend the same kind of "anything goes" approach to revisions as they do to writing.
While I (and most others) are all for first drafts in which anything goes and nothing matters but the words on the page, revisions should be approached more carefully. There are many moving parts in a novel that need to be in perfect alignment if you want the smoothest, most enthralling story for your readers. You need to have characters that are well-developed and (usually) follow a character arc, a plot that hits the major plot points, and a theme that comes organically out of the characters and plots.
It can be overwhelming to think about everything your novel needs when you first sit down to re-read what you've written. The most important thing you can do is realize what you have accomplished. Think about the strengths in your story. Consciously dwell on the pieces you're most proud of--whether it's a specific line, or a plot twist, or a fascinating character you just love. You've already done more than most people ever will: you've written a novel!
There are lots of successful writers who use intuition in revision, but if it's your first go of it, or you like a little more structure, I recommend finding a revision process that works for you. I use the detailed revisions process laid out by Susan Dennard as a jumping off point, which has evolved over time to suit me.
A Google search for "Revising your novel" leads to a lot of x-step guides to a finished novel. Holly Lisle, for instance, says she edits a full novel in one to two weeks and if you're taking more than a few months you're probably doing it wrong. I disagree with her, especially if writing isn't your full-time job. Many of us, myself included, simply don't have the time to devote 6- to 8-hour days to working through our manuscript. Take the time you need to take. That said, she offers excellent advice (set a realistic deadline for yourself; write the best book you can now, without worrying about the best book you can write next year) and some great questions to ask as you re-read. Despite the title, Anne Lyle's Revising Your Novel in 10 Easy Steps doesn't overly simplify the process, but gives you a great place to start and concrete steps toward making your book the best it can be.
If you either enjoy consciously plotting story structure or don't understand much about it, K.M. Weiland's website, Helping Writers Become Authors, is my go-to website for learning about structure. There are series on structuring the whole of a book, structuring scenes, and structuring character arcs, as well as a database of examples and a plethora of other things. If you don't know what to look for when it comes to making sure your story holds together, her website is an excellent source.
However you choose to go about revision, there are a few things to remember:
- Always revise big picture first and details last. If you have to add a new scene, treat it like a new first draft, making sure the right things happen before making sure dialogue is perfect before making sure typos are absent.
- There comes a time when you will need to show your work to critique partners and betas. This is absolutely necessary before sending to agents or out for self-publishing. For me, this step is after my second draft, when I've done my revision for the big picture and tackled much, but not all, of the smaller issues. For you, it might be after the first draft, so your critique partner can work as a sounding board for how to change things. It could be as you write, chapter by chapter. It might be after your fifth draft. What matters isn't the timing, it's making sure you get someone else's opinion.
- Revise again after you receive feedback. Probably set it aside for a few weeks and revise another time after that. Revise until you're not sure you like the story anymore. Then stop, trust yourself, and head over to QueryTracker to start querying. That's when you'll be ready.