You've finished your first draft and in your mind's eye your book is done. Wrong. Now is actually the time to step away and celebrate your victory of getting this far. Disconnect from your book for a few days, watch mindless TV, catch up with friends, and get back out there in the world before you return to your book. This break allows you to view your book with fresh eyes to discover if what you wrote is indeed what you really meant to say.
You'll discover amazing surprises that enforce your acumen as a writer. Don't be discouraged by the turns that lead your internal voice to say, "I can't do this! What was I thinking? I suck!" The proofing, editing, and rewriting stages can feel like drudge work, and it's important to keep a positive attitude while at this stage and be assured that most first drafts start out clumsy. It is through the revision, the novel finds its focus and cohesiveness. This process allows you to discover what's important and inspiring to the story, how the writing flows, while uncovering the larger theme, and how your characters evolve to become believable human beings. Discovering what you said, and what you really meant to say, oftentimes, is not about what you want the story to be but more about what the story wants to be. The revision is the stage wherein you can see your work in new ways and go deeper into your creation, so that the rewritten draft will be even stronger and closer to your vision for the story.
Pay attention to how certain characters make you feel, and the parts of the text that ignite those feelings, then consider what those feelings imply to the story, while recognizing what's important to pursue versus what should be minimized or omitted altogether. The read-through and revision are the discovery stages. What you discover actually makes your job easier to see the novel take on its final shape.
Roll with it; you'll be inspired by what you discover.