When should you use a comma? Here are some examples.

• Before a coordinating conjunction (FANBOYS) that is joining two independent clauses: IC, cc IC.
  We went to the store, and we went to the play.
• After introductory words (or word) (often DC, IC):
  Since I was hungry, I went to the pizza place.
• To set off “nonessential” information:
  Fred, who lives next door, is a very nice person.
• To set off conjunctive adverbs that are asides (they interrupt the IC):
  She was, moreover, very tall.
• To separate three or more items in a series:
  We ate pizza, fries, and cake at the party.
• To separate two or more adjectives of equal weight:
  The fat, happy puppy was wagging his sort, stumpy tail.