Punctuation

Commas 

• use before a coordinating conjunction to connect two independent clauses
• use to separate words, phrases, and clauses in a series
• use between adjectives that modify the same noun
• use to set off unrestrictive modifiers (modifiers that can be removed without changing the meaning of the sentence)
• use to set off substitute or contrasting phrases unless they are connected by a conjunction
• use after a long introductory phrase
• use to separate two subordinate clauses that work together
• use in a date if the order is month, day, year
• don't use in a date if the order is day, month, year, or if just the month and year are used
• don't use between subjects and verbs or verbs and objects
• don't use to separate compound subjects, objects, or verbs
• don't use in page/line numbers, addresses, and four-digit years

Semicolons

• use between independent clauses not linked by a conjunction and comma
• use in a series where the items in the series contain commas within them

Colons

• use to introduce a list, the statement of a rule, or an clarification of what was just said
• use to introduce a quotation that does not fit in with the rest of the sentence
• use to introduce long quotations that are set off from the main segment

Dashes and Parentheses 

• dashes are usually typed as two hyphens with no space before, after, or between them
• use to surround a phrase that messes up the reader's train of thought
• use around a section that may be misinterpreted is surrounded by commas instead
• use dashes to introduce a phrase that explains a part preceding it
• dashes may replace a colon when introducing a series or list

Hyphens

• use between an adverb and the adjective in a compound adjective only if the noun it modifies follows it
• use between a number and noun in a compound adjective if it comes before the noun that it modifies
• use in compound adjectives if it will prevent misinterpretation
• use between two nouns that describe a single thing
• use in centuries if it modifies a noun
• do not use between two nouns if the first noun modifies the second
• do not use in a compound adjective if the adverb in it ends in -ly, too, very, or much
• do not use after prefixes unless: it separates the prefix from a word starting with a capital letter, the word might be misunderstood without the hyphen, or there would be a double vowel

Apostrophes

• add -'s to singular nouns, irregular plural nouns, and proper nouns to show possession
• add -' to show possession in plural nouns ending in s and proper plural nouns
• add -'s to the last noun in a series if the ownership of a certain item is shared
• add -'s to each noun in the series if the ownership is not shared
• use to show the plurals of letters in the alphabet
• do not use to show the plurals of abbreviations or numbers

Quotations

• use around a word or phrase that is used for a unique purpose in the sentence
• use around translations for foreign words

Brackets

• use around a parenthesis within another parenthesis

Slashes

• use between two opposite words unless they modify another noun, in which case use a hyphen
• use to separate parts of a poem used in a quotation

Periods/Question Marks/Exclamation Points (placing)

• put the question mark within a quotation if the quotation is a question
• put the question mark outside the quotation if the sentence containing it is a question

Spacing 

• it is allowed to put two spaces after any concluding punctuation