You most likely know the definition, but here it is from Merriam Webster
One of a pair of punctuation marks
“ ” or ‘ ’
used chiefly to indicate the beginning and
end of a quotation
When writing a lot of dialogue, it's easy to miss the occasional quotation mark, or even to add an extra. When editing that dialogue, it's easy to miss it again. In fact, more missing quotations can appear when you're rearranging sentences.
Readers tend to notice those missing and extra quotation marks, bless their little hearts.
While discussing this problem with a good friend, she mentioned a method to catch all of the mistakes with quotation marks. It's a bit tedious, but highly effective.
ctrl-f, or the find function.
Here is a screenshot of my first book in which I have 4649 quotation marks (I'm currently re-editing it). That alone is an indication that there's an error. As you may have deduced, there should always be an even number of quotation marks.
So far, I've only found 2 missing quotations in the first 1000 words, but there will be more. In my last 2 books, I had 23 errors in over 7000 quotation marks and 37 errors in over 6000 quotation marks.
How to perform the search
Now as you might imagine, 5,6, or 7 thousand is a lot of quotation marks to do a search on. I developed a rhythm of double tapping. That was better, but still not efficient enough. I then developed a rhythm of multiple double taps. taptap, taptap, taptap, taptap. At the end of each double tap, I should be at the end of a sentence and the search number should be an even number. If not, then I know I missed one or have an extra. I go back over the last few sentences and fix it.
This is still tedious and takes a half hour to an hour to complete. I switch from right hand to left hand about every 1000 quotation marks.
That's all there is to it.
It's fairly simple, but that's it. It's the very last step I take before formatting and publishing. It's one of those details that sharpens the quality of your book. It will improve the readability and make it so the reader is less likely to put your story down and go off to do other things.
All my best,
John H. Carroll