Always place a comma or period before beginning or ending quotation marks.
Incorrect: "Ned", he requested", please take this to Mr. Green".
Correct: "Ned," he requested, "please take this to Mr. Green."
Always place a colon or semicolon after ending quotation marks. (This is relatively rare.)
Correct: George claimed, "I have twenty points"; Bill said he had only twelve.
See also Question Marks and Exclamation Points in Quotations, Colons with Quotations, and Commas with Quotations.