You'll probably be amazed at all of the errors you detect when you are not concerned with content, meaning and story-telling artistry.
I aim my eyes at the nine-o'clock position and make a clockwise scan on each page, but do what works best for you.
Check your book for these bloopers:
- Wrong typefaces, particularly when text is pasted-in from another source
- Commas that should be periods -- and vice versa
- Straight punctuation that should be curly "typographers' marks"
- Curlies that curl in the wrong direction
- Missing spaces between paragraphs or sections
- Bad justification in the last line of a page
- Chopped-off descenders where you decreased line spacing (leading) or if the bottom of a text box is too close to the text
- Wrong-size bullets
- Too-big word spacing
- Normal letters that should be ligatures (more for large type than in body text).
- Accidental spaces after bullets
- Improper hyphenation
- Roman text that should be italic, and vice versa
- Ignoring highlighted warnings in MS Word.
- Automatically accepting MS Word suggestions
- Gray text that should be black.
- Insufficient space adjacent to images
- Images or text boxes that floated over the margin.
- Images or text boxes that 'slid' down and covered up footers
- Missing periods at sentence ends
- Missing opening or closing quote marks.
- Periods that should be inside a closing parentheses -- or outside
- Repeated words
- Wrong headers, missing headers, switched verso and recto headers
- Subheads that are too close to the text above and too far from the text below
- Too much space between lines in a multi-line title, chapter name or subhead
- Pages with numbers that should not show numbers (blind folios)
- Words that shifted from the bottom of one page to the top of the next page
- And one that does require reading: chapter names in the table of contents that don't reflect a change made in the actual chapter name
- And another: chapters missing from the TOC.
- And another: a topic not in the index because you added something after completing the index
- And another: words that should have been deleted but were not, and may have accidentally been shifted into another part of a paragraph
(Eye photo from Microsoft. Thanks.)