1. COMMAS
When to use them…

2. SERIES
Use a comma to separate the elements in a series: (three or more things)
Example: He hit the ball, dropped the bat, and ran to first base.

3. INDEPENDENT CLAUSES
Use a comma + a little conjunction (and, but, for, nor, yet, or, so) to connect two independent clauses.
Example: He hit the ball well, but he ran toward third base.

4. INTRODUCTORY ELEMENTS
Use a comma to set off introductory elements.
Example: Running toward third base, he suddenly realized how stupid he looked.

5. PARENTHETICAL ELEMENTS
Use a comma to set off parenthetical elements (a part of the sentence that can be removed without changing the meaning of the sentence).
Example: The Founders Bridge, which spans the Connecticut River, is falling down.

6. Appositives as parentheticals
Appositives are almost always treated as parentheticals.
Examples: Calhoun’s ambition, to become a professional goalie, is within reach.
… Eleanor, his wife of 30 years, decided to open up her own business.

7. COORDINATE ADJECTIVES
Use a comma to separate coordinate adjectives
Example: That tall, distinguished, good-looking fellow (as opposed to little old lady)… rule: if you can put an “and” or a “but” between the adjectives, a comma will probably belong there.

8. QUOTED ELEMENTS Use a comma to set off quoted elements.
Example: “The question is,” said Annie, “whether you want to go or not.”

9. WORDS THAT CONTRAST Use commas to set off words that express contrast
Example: The puppies were cute, but very messy… or
Some say the world will end in ice, not fire.

10. AVOIDING CONFUSION Use a comma to avoid confusion (Also…see Rule #3)
Example: Outside the lawn was covered with broken branches.
Outside, the lawn was covered with broken branches.

11. USE COMMAS WITH CAUTION
The biggest problem that most students have with commas is their overuse.
Try not to use a comma unless you can apply a specific rule to do so.