You know when you’re reading something and you think to yourself: “Pff, this guy doesn’t even know how to spell”. Yes, admit it. You’ve done it because we all have at some point.
I myself am a bit of a grammar nazi sometimes, but only when I’m absolutely sure of the rule. I think this only reflects on my own insecurities, so I make a big fuss out of it to hide my other mistakes.
When I first finished my first book I let it simmering for about a month before thinking of reading it again. In the meantime I worked on other things and tried to forget about it because I knew the rule: never read something you’ve just wrote because you’re not going to catch the typos and general mistakes.
After a month, I was ready to give it a go. And then I gave it to two friends of mine to be my beta readers. It was a great help and I corrected a lot of things thanks to them. And then I published the book just to find a couple of days later that I had written “stake” instead of “steak”. I was mortified.
Our brains are funny. They are always trying to find shortcuts to do things even though they are extremely powerful, analog computers. So, when we think we’re reading a word, in reality we’re picking up just enough letters to identify the word. Then, we carry on to the next one, and so on and so forth. That’s why we can read something a hundred times and not spot a mistake: we are not actually reading the entire word, just parts of it.
So, word of advice: don’t try to edit after you’ve just finished writing something. Let go of it. Give yourself the opportunity to forget about it so you can spot your mistakes. Also—and I can’t stress this enough—give your manuscript to someone before publishing. A fresh pair of eyes is extremely important not only to spot typos but also to give you insights on the structure of the narrative and plot holes you’ll never know are there otherwise.
Think of it like being the book’s grandmother. You’ll never be able to see all of its mistakes because you love it so much.