In The Artful Edit, Susan Bell talks about two major kinds of editing, macro-editing and micro-editing. I find it interesting that though I usually test as a "big picture" person, I prefer the micro-edit. Bell writes that she also does, and that F. Scott Fitzgerald, whose The Great Gatsby she examines at length in her discussion, was also a natural micro-editor. Be that as it may, we mustn't skip over the macro-edit, which, as long as you have a good chunk of the book done, comes first. :)
The macro-edit isn't an edit-as-you-go thing. You need a substantial number of chapters, if not the whole draft, that you'll reread and note the big stuff that isn't working: characterization, tension, tone, and so forth. One of the more interesting aspects of the macro-view is what Bell calls "intention." Synonyms she uses include "overarching aim," "central idea," "your mind's highway," "a main line for readers to go down," and "a kind of gravitational force" that draws the reader through the story. To discover or refine your intention Bell recommends asking questions such as "What am I trying to do here?" "Where am I going with this?" "Why do I want this piece of writing to live?" Sometimes the intention is quite grand. Fitzgerald wrote that he was trying for a "consciously artistic achievement." But I believe we need a specific intention for the story itself as well. The intention can be unknown at the start, says Bell, it can be discovered through exploration as we write the draft, but when a writer begins to edit "he knows the story he wants to tell and maneuvers his material to tell it . . . Once there is story, there is an intention: a will toward . . . [an] end."
We need to spend some time talking to ourselves about our intention. Our attempts to state it may seem incomplete, a tad mysterious or secretive, something we wouldn't want to try to voice to others yet or even squarely face ourselves. But we can and must tease it out of our hearts; it forms the backbone of our story.