The enemy at this point is a simple fact of life: with every pass through a novel, our blinders grow more tightened to anything we've missed. We're quite right to search with new fury for typos, spellos and grammos that have slipped past our eagle eyes. At the same time, though, we need to renew our hunt for wrongos that can undo us: inconsistencies, lapses in logic, glitches in the timeline, etc.
I'd also add to this list small wait-a-second spots. These are especially deadly for writers of suspense, for they break the charmed narrative spell and cause readers to scratch their heads in wonder: Wait a second, haven't we established that the character's wearing brown socks and not green?...Wait a second, now the author's saying that his character was warned by X about Y two or three chapters ago? Where's the warning hidden?...Wait a second, the hero was listed as fourth on a list of seven victims--and now he'll be the third to go?
Wrongos occur for good reasons sometimes, A character was dropped, for example, resulting in the changing of a list. Or the timeline was condensed to add some more oomph to the story or simplify things for the reader. And, not to be too unkind to ourselves, wrongos are inevitable when we're spending months, even years, on our books. Even with the best of charts, our characters' eye colors may change on us...or, God save us, we may forget the color of their socks.
I'm happily hunting for wrongos these days as I work on RC, my new winter release. And each day's work starts with this mindset: small slips are waiting to get me and I need to take them down. I owe that to my readers.