Continuing our discussion of punctuation, commas deserve a little more attention.
Remember: commas primarily offset parenthetical material or separate items listed in groups of three or more.
Pay attention to subtle detail: "My brother, Patrick, and sister Maryelizabeth live nearby". Since Patrick is surrounded by commas, he is the author's only brother. The lack of commas around Maryelizabeth denotes that she is one of multiple sisters.
Add a comma at the end of full dates and places, unless they are placed at the end of a sentence (He moved to Chicago, Illinois, on June 6, 2002.)
An Oxford comma is a comma before and in a list (Shakespeare wrote plays, sonnets, and narrative poems.) Editors can use the Oxford comma or omit it; Wikipedia only asks that each article be consistent.
And finally: A sentence with a lot of commas is a sentence that needs to be rewritten more simply.