This one is important!
A fellow performer (I’m a classical violinist) once told me, after a concert, that there is no such thing as a perfect performance. I keep that in mind every time I play, give a talk, or write a book.
My opinion is that no one has ever published a perfect book. No matter how many proofreaders you employ, editors you hire, times you go over your deathless prose, a mistake can slip through—and often does.
I have my own methods for trying to catch as many as I can. I’m a fast, careless typist, so there are quite a few to catch. Beta readers are a must for me, as are critique groups when I have time.
Here’s my best tool. I open my document in one screen, and have my computer read it on another one. ReadPlease software used to be free and that’s what I still use. I can paste several pages of text into it at a time, then follow along on the other screen while it reads to me. When I catch something, I pause it, correct, and resume the reading.
I think reading aloud might serve the same purpose, but I think my voice would wear out if I were doing a novel.
Do you have good methods for proofreading? Something others could use?