addendum: something from the comments struck me about deleting unneccessary bits and scenes. I always compile a "deleted scenes" file that I sometimes refer back to. But most importantly, if a "darling" really sticks out in your head, a line of dialogue or an exchange or certain showing behavior (I'm more ruthless with narrative because even if I like the writing, it's usually telling that I've fallen in love with) I work it in somehow. Much of making art well is craft, but have faith in your instinct.
I learned a cool revision trick from Carol Berg--print your book out like a paperback, mirror margin, and read it where you usually read, not where you work. So I did and I am. It's really cool to see it in that form. Mistakes and inconsistencies leap off the page, and yet, I find myself getting into the story all over again. I've also found it easier to separate myself from the story in that form. My brain is trained to "read" in that form, not revise, so I can make notes without feeling that internal "I'm an idiot" twinge. Try it; you might like it!
Carol's one of my favorite writers, and just an all around nice person. She's all too willing to chat to anyone, struggling or successful, and her talks are fascinating. She's a thoughtful, intuitive fantasy writer, and if you've not read her, I highly recommend her books. I heard her talk on revision at CO Gold Con, and she made an outline of items to revise by so handy that I've kept my notes open on my desk since I began the arduous process of revising Sentinel.
On early pass-throughs you check for overall Structure--order of narration and events. Balance--does the tension build and is the length of book proper to the story? Coherence--does it tell enough, explain? This is narrative vs dialogue. (this is my greatest issue to date--I'm dialogue-heavy, if you wondered). Are Transitions smooth? Flow, time gaps, and do you set each scene? (another personal failing). Narrative Sequence- is the time order clear? Sometimes plots jump back and forth, so is the reader grounded? Should action be re-ordered to make it clearer, because clarity is key here. Is the Feel/Mood for each scene as intended? (I generally do a plot outline at some point and judge the tension of each scene against the tension of others. Sometimes readers need a break, you know?)
She recommends making a list of each character and the subplots surrounding them--I tend to do this early on, so I skipped this step. This is really necessary for pantzers, though.
We should check minor characters, though. Do they live beyond the page? Are they individuals, or do they just fill space? I think about this a lot because I have recurring minor characters in a four-book series, and so they need to seem real and grow, too. The best way I've found to do this is to put them in conflict with your protags so we can see them in action.
Detail Structure--This is about story arc. Again, I tend to do this work in synopsis form early in the process, and with Sentinel I know the story quite well, so I've not outlined my arcs. Fortunately, my critters haven't recommended I do this either, so I must be okay on that front.
Then we get down to the nitty-gritty of each scene. Is everything in every scene NECESSARY? Very important. Short story writing will train you to rigorously delete extraneous prose. Everyone needs to work on this, everyone.
Does the tension mount? Does the choreography make sense? (This is where I find critters particularly useful. I get comments like, "Uh, yeah, he forgot to put his pants on. He's been nekkid since page FOUR!!")
Dialogue--is it tagged or obvious who's speaking because they use the other's name? (Don't use the names too much--when people do that in RL it's condescending.) Is some of it embedded in action--not flowery, but just to keep the characters moving and gesturing? (I like to set my characters a task: pack a bag, walk across a yard so that they'll spot something important, putting off answering a ringing phone because they're listening to the other character adds tension, or avoid looking at the proverbial elephant in the room. I've found such secondary behavior forces my characters to act and shows their emotional state, as well as builds tension and keeps the plot moving. I've found several instances where my dialogue sequences fail on this count.)
Setting and Detail--I find my setting descriptions tend to reflect the story and mood pretty acurately. This seems to be some unconscious symbolism I employ--probably horribly obvious to a professional.
She also highlights all backstory and exposition. Interesting tactic, that. I don't tend toward lots of narrative and exposition, so I generally skip this step. But still, it would be interesting to see.
These are under "Tighten your prose:" -ly searches and lists of adjectives searches. Set a goal to delete one line from every page. Destroy weasel words: always, almost, very, that. Also, pay close attention to your personal weasels. Mine are characters looking at things or each other, anything to do with eyes in general, and trading one emotion in exchange for another (sadness edged out by curiosity, fe). This is knowing yourself as a writer. Again, EVERYONE does this. Everyone. No one is immune from this sort of repetition in drafting. Catching it in revision is a sign of mastering your craft, in my opinion.
Do you complete the Contract with your reader? Do the last three chapters satisfy the questions raised in the first three? Read just those six chapters and find out.
READ IT OUT LOUD. To your dog. To your husband. To yourself. Whatever. READ IT OUT LOUD.
Find out if your characters sound different. Do different POVs have different rhythms and thought patterns? Is their internal dialogue focused on their own concerns and personality? Do they speak differently than one another?
Then, of course, have someone else read your book. I utilize a talented team of writers and some just-plain readers, and they all come up with different things for me. Very useful.