I don't always get it right, but here are some punctuation rules for anyone interested in improving their writing skills. (Should I have said "there" instead of "their"?)
- Periods and commas always go inside the closing quotation mark. This is the preferred American style. (Some writers in the US follow the British style: Place the period outside when it punctuates the whole sentence, inside when it punctuates only the quoted material.)
- Semicolons and colons always go outside the closing quotation mark.
- Question marks and exclamation points go inside or outside the quotation mark, depending on its usage. Place the mark outside when it punctuates the whole sentence, inside when it punctuates only the quoted material.
I go by the Greg Reference Manual, American style.