You are using the wrong quote marks
Using the wrong quote marks is one of the most common errors I see. Especially true in books not professionally typeset. Depending on the font you are using it may be more or less visible that you've used the wrong quote marks. But either way, no author wants to have errors in their work. It distracts readers from the brilliance of their story. I've highlighted that before in Proofread Like A Boss.
There are two types of symbols that look very similar and yet they actually have very different meanings.
Quote marks, single quotes, and apostrophes are either curled, or slightly slanted. They are commonly confused with prime marks, the symbols which are used to denote feet and inches, hours or minutes.
I've also seen quotation marks incorrectly used when describing the height of a character. It is correct to use prime symbols for height as they denote feet and inches.
The key to avoiding the wrong quote marks is to know the difference and to know how the mistakes creep in. What is really frustrating is keyboards only show prime symbols. I can already hear you wondering, in that case, how the hell you've ever used the curly ones. Most word processing software will convert a prime symbol into a quote mark or apostrophe appropriately. And that stops us using the wrong quote marks most of the time. But you will have to undo this auto correct if what you actually needed was a prime symbol to denote feet and inches.
Where things really go wrong is for those of us who use various mobile devices or web text editors. Many of those will only display prime symbols. If you do a lot of writing or editing that introduces the wrong quote marks into your work then there is an easy way to correct it. Using something like Microsoft Word, and the find and replace feature, you can go through your work and search for all the prime symbols and replace them with quote marks. Just be careful to not replace correctly used prime marks where, for instance, you've described the height of a character.
One last thing to point out is that many websites will incorrectly use prime marks as they don't have the automatic functionality to correct them like a word processor. However, if you are keen to have the correct typography on your website or blog then there are various plugins that are available. I use the TinyMCE Advanced plugin. It comes with a whole host of other features that upgrade the functionality of the visual editor.
If you've experienced these issues and need help, just drop a comment below and I'll be happy to help. Or have you found your own solution to deal with this that you can share?
Yeah, in some ways the way that software tries to automate this contributes to the problem. Microsoft word uses the language "straight quotes" and "smart quotes" to distinguish these. One can set the preferences for Word to use one or the other by default. The ways in which I find documents get messed up include: editing the same file on multiple machines with different default preferences (or different versions of Word), and copying and pasting from one program to another (e.g. typing a snippet in notepad or onenote and then copying it into Word).
Sam, I reckon you know this tip, but I had to search it out: If you want to fix all the quotes within the document to use smart-quotes, you should first change the preferences to use smart-quotes by default, then do a search and replace, using " in both the search and replace fields. It doesn't matter that the quotation marks look exactly the same in the search and replace box, you're replacing quotes with quotes, but this forces Word to replace using the latest preference setting you used. You can do a replace all to process the whole document. You can do the same with single-quote '.
Of course, if you actually do need to use the prime-marks (a.k.a. "straight-quotes") as they were intended, in only a few cases in the document, then you'll have to fix those separately, probably by using insert-symbol, or a cut and paste operation (type a quote/prime in notepad, cut it, paste as text-only). In theory you could make these special cases somehow searchable, maybe by giving them a separate style or adding notes.
If I'm clever enough to stay properly organized, I make correcting quotes the last step in editing after every other detail is polished. Once you've got it all fixed in Word, if you're designing for print, you can use that file as the source for InDesign documents and the proper quote forms should carry over.
Oh yeah, and if you are silly enough, like me, to design your ebook version by coding the html and compiling it, straight-quotes vs. smart-quotes becomes a new mini-nightmare. I try to use word to add in some tags before saving as a text/html file, but I've learned to watch out because, while I want smart-quotes for the novel text, you need straight-quotes within some of the html tags, such as html styles. Bleh.
It seems, for all the great development in word-processing and publishing software, nothing was designed specifically with the needs of novel-writing and -design in mind, and everyone has to learn from scratch with minimal guidance.