Something else I have to be aware of when I polish a book is consistency. For instance, if I've said a character's eyes are blue in one scene, they'd better be blue in a later scene.
This is what I call minor consistency, and I generally make notes of such details as the book progresses.
Even more important is character consistency. We want our main characters to grow and change in emotional ways during the course of a novel. That's good. What we don't want is for a character to suddenly change or behave in a way we're unprepared for simply because the author wants the plot to move in a certain direction. It's disturbing if a heroine set up as bold and take-charge suddenly does something stupid, like wander around a dangerous place alone and unarmed, because otherwise, how could the villain find her? That's a change in character solely for the author's benefit, and the character is the lesser for it,
I'm also looking for plot consistency, making sure that if I've had something happen to a character in one scene, it effects them in the next. You might think this is an easy thing to avoid. I don't generally have this problem with what happens to my characters emotionally, but I can overlook physical things sometimes. For instance, in the book I just finished, the heroine has badly sprained her ankle in a scene. In the next, she's fine. It's a miracle! No, it's a mistake. I forgot about the injury when the time came to write the next scene. Fortunately, I remembered the ankle in a later draft and now she's hobbling around for awhile.
As with unity of voice and pacing, I generally find the inconsistencies when I've finished a complete draft or two. Until then, I'm still "feeling my way" with the characters and story elements, paying more attention to them than things like eye color and minor injuries. But that doesn't mean that consistency of minor elements isn't important. Anything that disrupts the reader is a problem that has to be fixed.