I copied this the other day from a post on here. Maybe it will help with the other seven. I can not remember who first posted this. Sorry.
A comma has seven specific purposes:
- To separate items in a list
ex. I like apples, oranges, and bananas.
- To connect two independent clauses
ex. She walked into the road, and a car clipped her.
- To attach a dependent clause to the beginning of an independent clause
ex. Following World War II, the United States became a leading world power.
- To separate two adjectives
ex. Blood dripped from her sharp, yellow teeth.
- To show a change of direction in a sentence
ex. The queen viewed herself as omnipotent, not a pushover.
- To separate states from countries, names from titles, and dates when written in full
ex. I visited New York City, New York.
ex. Steve Nash, starting point guard for the Phoenix Suns, won MVP in back-to-back seasons.
ex. The day is September 19, 2009.
- To separate a quote from its introduction or explanation
ex. She peered over his shoulder and asked, "What are you writing?"
ex. "With a little bit of practice, commas aren't too tough," he said.
There are exceptions to these rules, but this will help you get started. Good luck!