1. Use apostrophes correctly
Maybe it’s because of its diminutive size, but the apostrophe tends to be neglected and misused in equal measure.
The apostrophe is used to form possessives (e.g., the school’s faculty, our family’s crest, the shirt’s collar, Bill Thomas’s house) and certain contractions (e.g., it’s, let’s, she’s, they’re, I’ve, don’t).
The apostrophe is not used to form most plurals (e.g., she is looking at several schools, the families have similar crests, these shirts are on sale, we are dining with the Thomases). There are three exceptions: plurals of lowercase letters (e.g., dot your i’s and cross your t’s); plurals of certain words used as words (e.g., we need to tally the yes’s, no’s, and maybe’s); and plurals of certain abbreviations (e.g., the staff includes a dozen Ph.D.’s and four M.D.’s).
2. Know where to place quotation marks
Periods and commas go inside quotation marks, even if they aren’t part of the material being quoted. Colons and semicolons go outside quotation marks.
|Punctuation mark||In relation to closing quotation mark, place it…||Example||Notes|
|Period||Inside||Participants who kept dream diaries described themselves as “introspective” and “thoughtful.”|
|Comma||Inside||Many dream images were characterized as “raw,” “powerful,” and “evocative.”|
|Parentheses||Outside||Barris (2010) argued that “dreams express and work with the logic of gaining a sense of and a relation to ourselves, our lives, or our sense of reality as a whole” (p. 4).||See more examples of how to cite direct quotations here.|
|Semi-colon||Outside||At the beginning of the study, participants described their dream recall rate as “low to moderate”; at the end, they described it as “moderate to high.”|
|Colon||Outside||Participants stated they were “excited to begin”: We controlled for participants’ expectations in our study.|
|Question mark or exclamation point (part of quoted material)||Inside||The Dream Questionnaire items included “How often do you remember your dreams?” and “What do you most often dream about?” We found intriguing results.||When a quotation ending in a question mark or exclamation point ends a sentence, no extra period is needed.|
|Question mark or exclamation point (not part of quoted material)||Outside||How will this study impact participants who stated at the outset, “I never remember my dreams”? We hypothesized their dream recall would increase.|
|Quotation within a quotation + period or comma||Inside||Some participants were skeptical about the process: “I don’t put any stock in these ‘dream diaries.’”||When multiple quotation marks are used for quotations within quotations, keep the quotation marks together (put periods and commas inside both; put semi-colons, colons, etc., outside both).|
3. Know how to punctuate with parentheses
When a parenthetical element is included at the end of a larger sentence, the terminal punctuation for the larger sentence goes outside the closing parenthesis.
When a parenthetical sentence exists on its own, the terminal punctuation goes inside the closing parenthesis.
She nonchalantly told us she would be spending her birthday in Venice (Italy, not California). (Unfortunately, we weren’t invited.)
4. Use a hyphen for compound adjectives
When two or more words collectively serve as an adjective before the word they are modifying, those words should normally be hyphenated. The major exception is when the first such word is an adverb ending in -ly.
The hastily arranged meeting came on the heels of less-than-stellar earnings.
The colon and the semicolon can both be used to connect two independent clauses.
When the second clause expands on or explains the first, use a colon. When the clauses are merely related, but the second does not follow from the first, use a semicolon.
Semicolon: Only a third of Americans have a passport; the majority of Canadians have a passport.
Colon: Only a third of Americans have a passport: for most, foreign travel is either undesirable or unaffordable.
6. Avoid multiple punctuation at the end of a sentence
Never end a sentence with a question mark or exclamation point followed by a period. If a sentence ends with a period that is part of an abbreviation, do not add a second period.
I don’t particularly like the play Who’s Afraid of Virginia Woolf? I didn’t like it even when I worked at Yahoo! I especially didn’t like it when I saw it at 5:00 a.m.
7. Use a colon to introduce a list only when the introductory text is a complete sentence
Not all lists should be introduced with a colon. The general rule is that if the introductory text can stand as a grammatically complete sentence, use a colon; otherwise, do not.
Correct: Please bring the following items: a flashlight, a comfortable pair of hiking boots, and a jacket.
Incorrect: Please bring: a flashlight, a comfortable pair of hiking boots, and a jacket.
Correct: Please bring a flashlight, a comfortable pair of hiking boots, and a jacket.
Correct: Please bring the typical evening hiking gear: a flashlight, a comfortable pair of hiking boots, and a jacket.
8. Use commas to indicate nonessential information
If explanatory matter can be omitted without changing the general meaning of the sentence, it should be set off with commas. If the explanatory matter is essential to the meaning of the sentence, do not set it off with commas.
Correct: The novelist Don DeLillo seldom gives interviews.
Incorrect: The novelist, Don DeLillo, seldom gives interviews.
Explanation: The identity of the specific novelist is essential to the meaning of the sentence. Otherwise, there is nothing to indicate which of the multitude of novelists is being referred to.
Correct: America’s first president, George Washington, served from 1789 to 1797.
Incorrect: America’s first president George Washington served from 1789 to 1797.
Explanation: America has only one first president. Identifying him by name is not essential to the meaning of the sentence.
9. Use a dictionary
Is it U.S.A. or USA? Co-worker or coworker? Lets or let’s? Teachers’ college or teachers college? Though these examples implicate punctuation marks (the use or omission of periods, hyphens, or apostrophes), the correct form can be easily determined with a good dictionary.
10. If in doubt, rewrite
The easiest way to solve a vexing punctuation problem is to avoid it. If you aren’t sure how to properly punctuate a sentence—or if the proper punctuation results in a convoluted, confusing, or inelegant sentence—rewrite it. Perhaps as more than one sentence.