Trailhead: Stefanie Flaxman. Catch More Writing Mistakes with This Underutilized Proofreading Trick. Copyblogger (2015-07-01). (courtesy of Filament's Monday Morning Meeting, 2021-01-25)
The second suggestion in that article is: proofread backwards. Start at the end, then work back towards the beginning. Her point is that when you see the words you wrote in a different order, it's easier to spot errors. The words look fresh—not like words that you've read a hundred times before.
(Coincidentally, in the background, I just got Rob Walker's The Art of Noticing #62, How To Get a New Perspective, and it mentions "the fog of familiarity".)
But there's one more point I would add to that: it's tiring to read and review things, and over time you run out of energy, focus, attention. At some point, if you haven't quit, you're just trying to scrape by to get to the end, doing a progressively worse job.
In engineering, we have reviews for a variety of documents that we make—requirement reviews, test reviews, flight reviews, etc. A requirement specification for a complex aerospace system can easily run past 100 pages. Few people have the stamina to give page 100 the same time and attention as page 1. I've seen some reviewers just make comments about the cover page of the spec and leave it at that. (Thanks?) I've seen requirements at the end of a spec that referred to the wrong program, meaning that whoever put the spec together themselves didn't make it to the end to clean up the requirements they copy/pasted from another spec, nor did the reviewers who approved the thing before it was sent to us. I understand—reading a spec is murderously boring.
There is an easy solution, and it's one of my best review hacks. When I run a spec review, I recruit volunteers—some will start at the one-thirds mark, and some will start at the two-thirds mark. Then I have some assurance that the middle and end of the spec get some scrutiny.
That's it. It's a really superficial hack. It's not as good as putting in the work to make reviews better, but it helps.