Ha! As if we didn't make enough mistakes, there's more on my list.
6. Its and It's: This is a special case of the use and non-use of the apostrophe. It's is ALWAYS a contraction for "It is." Its, when used as a possessive, NEVER has an apostrophe.
7. Punctuation marks like commas and periods fall INSIDE the quotation marks. The outside way is British. If you're subbing to American publishers, it's probably best to stay inside the quotes.
8. Virgules (doubletake here! Someone pull out Balderdash! Ahem, back to the list.) So, ah, virgules are used to indicate alternatives, as in "and/or." A usage like "secretary/treasurer" suggests this person is either a secretary or a treasure, but not both. "Secretary-Treasurer" is the correct form. Most every usage of virgule you see today is incorrect. Professional writers know the difference between correct usage and incorrect usage. (ouch mr. editor! *snort*) When I posted this I took my editor's word for it but because of the comments I decided to look it up. Now I'm not sure my cheat sheet is write. Hmmm. Just thought I'd let y'all know. :-)
And the postscript of my cheat sheet which my wonderfully sweet former editor gave to me is just too funny to not share. For your viewing pleasure only, his last words to naive, first-time freelancer Jessica Nelson.
"If you leave too many errors for him [mr. editor] to correct, he may just decide that you really don't know what you are doing, and really start doing some aggressive editing, figuring 1), your work probably needs it; and 2), you'll never know the difference."
*He really was a nice editor. I wasn't being sarcastic. Just so you know, since you can't hear my tone. :-)*