Comma Guidelines
Use a comma:
1.) Before -- and / but / or / nor / for / so / yet -- when using one of these “coordinating conjunctions” to join two complete sentences together.
2.) Between -- all “items in a series” -- and, in academic writing, we use a comma before the "and" preceding the last item in the series (the “serial” or “Oxford” comma).
3.) After -- an “introductory element” (a clause or phrase) at the beginning of a sentence.
4.) Between -- “coordinate adjectives” (those not joined with “and” but which could be).
5.) To separate -- “nonessential material” (“nonrestrictive elements”) from the rest of a sentence.
6.) To separate -- “transitional words and phrases” from the rest of a sentence -- at the beginning, in the middle, or at the end of a sentence.
7.) To separate -- “parenthetical expressions” (instead of using parentheses).
8.) To separate -- “tag questions,” “names in direct address,” “mild interjections,” and “yes” and “no” -- from the rest of a sentence.
9.) To separate -- direct quotations from a “signal phrase.”
10.) To separate -- titles or degrees following someone’s name.
11.) Within -- dates and addresses and numbers.