This document provides an overview of common punctuation mistakes and guidelines for proper punctuation usage. It covers terminal punctuation like periods, commas and uses such as in lists. It also discusses quotation marks, hyphens, en dashes, and em dashes. Ellipses, apostrophes, semicolons, and colons are also covered. For each punctuation mark, common errors are identified and rules for proper use are explained. The document emphasizes carefully proofreading to avoid embarrassing punctuation mistakes.

2. Introduction
Ah, punctuation errors. Once a missed keystroke on a
typewriter, now the fodder of Internet memes, viral
screenshots, and endless Tumblr feeds. We’ve all seen the
public restrooms reserved for elderly pregnant disabled
children, the unsettling connotations of a restaurant that
serves “fresh” sushi, and the PR disasters that could have
been averted with critical commas. In an online world
where every little mistake is photographed and shared,
understanding punctuation is more important than ever
to maintain a credible reputation.

3. #1: Obey the
Terminator
(Periods and Terminal Punctuation)

4. Terminal punctuation can seem like a no-brainer, and it’s for
this very reason that many mistakes occur. Sometimes, we
overlook glaring errors simply because they’re so obvious. We
assume we haven’t made them and don’t think to check. There
are, of course, guidelines to keep in mind: Sequential
exclamation points are the written equivalent of shouting (right
up there with all caps). Some indirect questions actually end in
periods, not question marks, and different styles of writing use
different rules for terminal punctuation in quotes, parentheses,
or abbreviations. The bottom line? Proofread!
Periods

5. #2: A comma, a
comma. My
kingdom for a
comma!

6. This little devil is the culprit in the most infamous punctuation
blunders. Commas can be tricky things, what with the many,
many rules that apply to their usage. Some of the more common
gaffes are forgetting to include a comma between items in a list,
after introductory phrases, or between independent clauses joined
by a coordinating conjunction. If you’re thinking those mistakes
sound innocent enough, take a look at the magazine cover that
declares that Rachael Ray finds happiness in cooking her family
and her dog. Although the cover was found to have been
Photoshopped, this punctuation error is easy to make, so be
vigilant!
Commas

7. #3: Say “no” to
sketchy
quotation marks

8. I’ll say this once: Never use quotation marks for
emphasis. Inappropriate use of these teeny little marks
creates the written implication that something is, well,
questionable. If the text at hand isn’t actually a
quotation or the title of a work, using quotation marks
brings to mind the image of someone saying the word
or phrase while employing air quotes and waggling
their eyebrows. Would you eat at a grill serving “beef”
steaks?
Quotation marks

9. #4: Hyphens and
en dashes and
em dashes—oh
my!

10. Finding errors in the length of horizontal lines may seem like
nitpicking. Many won’t even realize these little dashes are
different! However, ignoring the circumstances that call for
hyphens, en dashes, or em dashes can lead to embarrassing
changes in the meaning of a written phrase. As a cheat sheet: Em
dashes (the longest of the three, equal in length to the typed letter
“m”) are used in place of commas or parentheses to create
emphasis. En dashes (equal in length to the letter “n”) connect
values or ranges (e.g., 2002–2008), and hyphens join words that
are logically connected (e.g., state-of-the-art, anti-war, long-
term relationship).
Hyphens

11. #5: Don’t
eclipse the
ellipsis

12. (For those of you who don’t get the reference, check out
this YouTube clip, and go watch The Rocky Horror
Picture Show as soon as you finish this article!)
Ellipses, consisting of three periods in succession, are
useful tools that allow writers to indicate an omission
(usually in quoted text), the trailing-off of a thought, or
a hesitation. As with exclamation points, the rule of less
is more applies. A page overzealously spotted and
dotted with ellipses will only look messy.
Ellipses

13. #6: Apostrophe
catastrophe

14. A pet peeve of editors, proofreaders, and grammar gurus
worldwide is the misguided use of apostrophes to form
plural nouns. Let’s take a moment to be absolutely clear:
Apostrophes denote ownership or conjoined words. Never
should an -s at the end of a plural noun be preceded by an
apostrophe. So please, noble writer, apostrophize the
teacher’s office, the dog’s bowl, and let’s get out of here, but
stay your hand when telling us about the 1980s or dinner
with the Andersons.
Apostrophes

15. #7: Serious
about
semicolons

16. (This is another reference for film buffs; if you don’t get the above
reference, you’ll enjoy it more after checking out this YouTube clip
from the 1976 movie Network.)
Semicolons represent a pause longer than that of a comma but
shorter than the full stop of a period. Before you start applying
semicolons willy-nilly, however, remember some simple rules: Use a
semicolon to join two sentences without a conjunction; before
transitional phrases, such as “meanwhile,” “however,” and “for
example,” when they connect independent clauses into a single
sentence; and in lists of this sort that include commas within list
elements.
Semicolons

17. #8: The dreaded
grammatical
colonoscopy

18. The colon means serious business. Mild toilet humor aside,
the use of a colon in writing is a signal that something
important is about to follow. Use a colon to introduce a list,
to lead into a second sentence that explains or adds to the
first without using a conjunction, or simply to add
emphasis to whatever follows. To make sure your colon is
clean (ew), you may wish to consult your style guide about
whether the sentence following the colon requires
capitalization.
Colons

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