• Always use the Oxford/serial comma.

• Ex.  dogs, cats, and rabbits (not dogs, cats and rabbits)

• If items in a series contain internal punctuation, separating them with semicolons can add clarity.

• Ex:  My heroes are Batman, who combines brains and brawn; Captain Picard, who commands respect; and Wiley Coyote, who never gives up.

• Etc. is preceded and followed by a comma when it is the final item in a series (same for its equivalents — so forth, and the like, etc.)
• I.e. and e.g. are preceded and followed by a comma.
• Set off adverbs with commas, unless the adverb is essential to the meaning of the clause or if no pause is intended.

• Ex:  however, therefore, then, next, etc.

• When independent clauses are joined by “and,” “but,” “or,” “so,” “yet,” or any other conjunction, a comma usually precedes the conjunction.

• Ex:  “Do we want to foster creativity, or are we interested only in our intellectual property?”

• If one sentence includes two commands separated by a conjunction, a comma should be used before the conjunction.

• Ex:  “Raise your right hand, and repeat after me.”

• If the sentence is separated by “and,” “but,” etc., and has one subject but two verbs, there should be no comma between the two verbs.  

• Ex:  Mary went to the store and bought a soda. 

• When a noun is preceded by two or more adjectives that could, without affecting the meaning, be joined by “and,” the adjectives are normally separated by commas.  If one or more of the adjectives is essential to (i.e., forms a unit with) the noun being modified, no commas are used.

• Ex:  “It is going to be a long, hot, exhausting summer.”  (It is going to be a long and hot and exhausting summer.)
• Ex:  “She opted for an inexpensive quartz watch.”  (“She opted for an inexpensive and quartz watch” does not make sense.)

• With an interjected phrase of the type “not … but” or “not only … but,” commas are usually unnecessary.
• Expressions of the type “that is/for example” are traditionally followed by a comma.  They may be preceded by an em dash or a semicolon, or the entire phrase that they introduce may be enclosed in parentheses or em dashes.

• Ex:  “Keesler managed to change the subject; that is, he introduced a tangential issue.”
• Material quoted in the form of dialogue or from text is traditionally introduced with a comma (a colon may also be used when the syntax requires it or to more formally introduce a quotation).  If a quotation is introduced by that, whether, or a similar conjunction, no comma is needed.
• When the context calls for a comma at the end of material in parentheses or brackets, the comma should follow the closing parenthesis or bracket.  A comma never precedes a closing parenthesis.
• Commas should be used following “if” clauses.
• Ex:  If the RM shows empathy and asks you why you do not wish to change, you will say that you do not want the hassle of installing new software.
• Ex:  If asked, you will agree to an implementation meeting next week. 
• Commas go inside quotes. 
• Exclude commas and quotes with “yes,” “no,” “thank you,” and similar terms.
• Ex:  She said yes.  (Not:  She said, “yes.”)

COLONS/SEMICOLONS

• Use a semicolon before “however” and “therefore” if what follows is a complete sentence

• Ex:  “They will buy bond funds; however, they prefer equity funds.”)

• Semicolons and colons go outside of quotes.
• Use two spaces after colons and one space after semicolons.

PERIODS

• Periods go inside of quotes.
• Use two spaces after periods.
• Phrases beginning with the word “To” (such as the objectives section in cases and proposals) should be bulleted and do not get a period at the end.  They are phrases, not complete sentences.
• Use periods after commands.

• Ex:  “Repeat after me.”

ELLIPSES

• Use the ellipsis “…” symbol instead of three periods with spaces between.  There should be a space before and after an ellipsis.