At my last critique group a member made the point that some books start thin and with revision get thicker. Convention wisdom in writing circles seems to hold that revisions ought to reduce the length of a book. You must kill your darlings, said William Faulkner. Well, I always found Faulkner wordy beyond belief. I think he could have killed off a few more darlings and his work would not have suffered.
I like Elmore Leonard's 10 rules of writing, especially number 10: Try to leave out the part that readers tend to skip. That being said, my writing suffers from the story remaining in my mind rather than going on the page. To overcome this I truly rely on members of my critique group to point out glaring (to them) gaps and inconsistencies. I am training myself to step outside my brain and be my own critic, but I'm sure I will always need (and want) an overseer.