The web is filled with tips for proofreading, so why reproduce that here?
The main problem, as I believe Mark Twain pointed out, is that the author (especially) or other reader does not see what’s on the page. He sees what his mind tells him is on the page—and that may not be the same thing at all.
Here is a tip:
Mix it up
If you have been proofreading in your word processor while sitting at your desk, switch to proofreading on a Kindle while sitting in an easy chair. Another pass through the book in a web browser may turn up problems that were invisible to you on the Kindle or word processor. Then, do it again by reading the “camera-ready” PDF in a PDF viewer.
One reason this works is that line breaks will fall at different places. For example, it is particularly hard to catch the doubled word if its first occurrence is at the end of a line and the second is at the start of the next line.
When I went outside, I saw the the big, orange, mean kitty cat.
If we are doing custom formatting for you, please note that we do not proofread your book. That is your job. Even if you hire out proofreading, we suggest you still do a final proofreading pass. After all, whose name is on the cover?
Even if you have already proofread your book, you must proofread it again after we have formatted it. We supply you with at least a Mobi file and an EPUB file. Read one or the other on an eReader (preferably) or an eReader App. If we also supply a “camera-ready” PDF, you must also proofread it in a PDF viewer.
Look for your typos, of course, but also look formatting errors. If we missed anything, now is the time to fix the problems. We offer revisions for two weeks at no additional charge. After two weeks, we charge for each revision.
typos (spelling, doubled words, missing words, missing space between words, incorrect spacing for ellipsis marks and em dashes, etc.)
curly double and single quotes facing the wrong way
lines that extend into the right margin (PDFs only)
line breaks that hypenate a word incorrectly
“missing” chapters (something you intended to be a chapter that we didn’t set as such)
Once you’ve found some problems, what should you do? Email us to tell us about the problems in context. Do not use page numbers. Instead, give enough surrounding text so that we can find the location of the problem by searching. You could give chapter name or number, indicate it is the first or third paragraph, etc. But be sure to give surrounding text.
This is not good:
missing ending quote mark end of 3rd paragraph on page 139
This is good:
missing ending quote mark after “night” in the sentence "It was a dark and stormy night, she said.
If you are doing your own formatting using our automated service, you can format early and often, catch not only your typos, but also find and fix any formatting problems as you go, so no last-minute rush or surprises.
When you proofread on the Kindle, you can highlight the problems while sitting in your easy chair, then move back to the computer to fix them in your manuscript.
Or, you can proofread on the Kindle until you find a problem, then immediately fix it in the manuscript. Back and forth, between Kindle and manuscript. Or between the HTML version and the manuscript. Or between the PDF viewer and the manuscript.
(Let us know if you have suggestions for this section.)