you would put the Oxford comma before the conjunction that concludes the list. It doesn't matter if the conjunction is "and" or "or," the Oxford comma would come directly before it. That's if you ...

More and more writers and publishers are joining newspaper editors in the belief that the second-last item in a series needs ...

If the person who is speaking is named before the speech, you must use a comma before the first set of inverted commas. Writers use direct speech in their stories to convey more about a character ...