When joining independent clauses with a coordinating conjunction — and, but, or, nor, yet, for, so — place a comma before the conjunction.
Wild April winds blew hard, and spring seemed stuck somewhere in the Carolinas.
The journey to the cafeteria took time, but time was a luxury [that Janey could ill afford].
The street was quiet as she walked that evening, yet through a curtained window she could hear Dylan sing the blues.
It seemed a perfect morning for a canoe ride, so he chose his favorite paddle and walked toward the dock.
The aurors would not surrender, nor would the dementors surrender.
Short independent clauses joined by coordinating conjunctions often drop the comma.
It was cold but it felt swell.
Janey ran and Dylan followed.
Go home and read books!
The final sentence: two indep. clauses or a double verb?
Worksheet using commas between independent clauses