The rules set forth in this section are customary in the United States. Great Britain is governed by quite different conventions. Nowhere is this more apparent than in Rule 3a in this section, a rule that has the advantage of being far simpler than Britain’s and the disadvantage of being far less logical.
Rule 1. Use double quotation marks to set off a direct (word-for-word) quotation.
Correct: “When will you be here?” he asked.
Incorrect: He asked “when I would be there.”
Rule 2. Either quotation marks or italics are customary for titles: magazines, books, plays, films, songs, poems, article titles, chapter titles, etc.
Rule 3a. Periods and commas always go inside quotation marks.
Examples:
The sign said, “Walk.” Then it said, “Don’t Walk,” then, “Walk,” all within thirty seconds.
He yelled, “Hurry up.”
Rule 3b. Use single quotation marks for quotations within quotations.
Example: He said, “Dan cried, ‘Do not treat me that way.’ “
Note that the period goes inside both the single and double quotation marks.
Rule 4. As a courtesy, make sure there is visible space at the start or end of a quotation between adjacent single and double quotation marks. (Your word processing program may do this automatically.)
Not ample space: He said, “Dan cried, ‘Do not treat me that way.'”
Ample space: He said, “Dan cried, ‘Do not treat me that way.’ “
Rule 5a. Quotation marks are often used with technical terms, terms used in an unusual way, or other expressions that vary from standard usage.
Examples:
It’s an oil-extraction method known as “fracking.”
He did some “experimenting” in his college days.
I had a visit from my “friend” the tax man.
Rule 5b. Never use single quotation marks in sentences like the previous three.
Incorrect: I had a visit from my ‘friend’ the tax man.
The single quotation marks in the above sentence are intended to send a message to the reader that friend is being used in a special way: in this case, sarcastically. Avoid this invalid usage. Single quotation marks are valid only within a quotation, as per Rule 3b, above.
Rule 6. When quoted material runs more than one paragraph, start each new paragraph with opening quotation marks, but do not use closing quotation marks until the end of the passage.
Example: She wrote: “I don’t paint anymore. For a while I thought it was just a phase that I’d get over.
“Now, I don’t even try.”
http://www.grammarbook.com/punctuation/quotes.asp
