The main use for quotation marks, of course, is to differentiate quotations and previously published material from an author’s original text. (When citing text that is three lines or longer, however, the standard convention is to offset and indent the excerpt without using quotation marks.)
Quotation marks also are used when referring to a word or phrase as the word or phrase itself and not what it means. For example:
USAID does not like its contractors to use the title “commercial sex workers” when referring to women who have sex for money because it believes the phrase destigmatizes the profession.
As for punctuation, periods and commas go inside the closing quotation mark regardless of whether or not they are part of the original quote. Unless they are in the text being quoted, however, colons, semicolons, question marks, and exclamation points belong outside of the closing quotation mark.
(Those rules for punctuation are for American English; in British style only punctuation that is part of the original quote goes inside the quotation marks. Yes, British style makes a lot more sense. But my website stats show that you probably aren’t British, so you’re stuck having to abide by the confusing and illogical American way.)
If a footnote or endnote accompanies the text, the reference number goes outside of the closing quotation mark.
And only use single quotation marks if text within a quotation needs a quotation mark.
Steve started to get jittery. He had just overheard his mom tell his dad, “And then Danny ran in and told me ‘Steve said a word you shouldn’t say.’”
Finally, do not use quotation marks for colloquialisms or buzzwords. According to The Elements of Style, “To do so is to put on airs, as though you were inviting the reader to join you in a select society of those who know better.” And no one wants to be thought of as “putting on airs.”