When I asked what was bothering her, she said, “Never mind[”.]
When I asked what was bothering her, she said, “Never mind[.”]
Incorrect ordering of punctuation marks:
Colons and semicolons go after the closing quotation marks, but periods and commas go before. Question marks and exclamation marks, more logically, go either before or after, depending on whether they are part of the quote.
If you find the placement of periods and commas after the closing quotation marks illogical, see Punctuation: FAQ for an explanation of the convention in American versus British English.
See Error Checklist for a compilation of 75 common writing errors.
For more exercises in identifying common errors,
take the M.B.A. exam and the Punctuation and Grammar Challenges.