Commas to Separate:
1. Commas separate two independent clauses joined by a coordinating conjunction (FANBOYS)
Mistake: John went to the store and Susan stayed home with the kids.
2. Use a comma after dependent clauses that come first in a sentence and after introductory phrases that are 4+ words long (or intro phrases that are confusing)
Mistake: When I looked into the mirror I got scared.
Mistake: Making an effort to be as quiet as possible I left the house.
Mistake: Inside the dog shook all the water off of himself.
3. Use a comma to separate words, phrases, and clauses in a series (3+)
Mistake: I bought a dress shoes and a purse.
Mistake: I went down the hall into the room and over to the table.
Mistake: Once I have eaten once I have slept and once I have showered we will talk.
4. Use a comma to separate adjectives not joined by “and” that modify the same noun (if you cannot switch them, they don’t require a comma)
Mistake: He is a handsome well-liked guy.
Commas to Set Off:
1. Use commas to set off adjectives in pairs that follow a noun
Mistake: The kids exhausted and hungry went home.
2. Use commas to set off non-essential (can be removed and the sentence will not change in meaning) words, phrases, and clauses
Mistake: The boy who was 12 had to go to the hospital.
3. Use commas to set off mild interjections like “oh,” “well,” “yes,” and “no.”
Mistake: Yes I am planning to attend the game.
4. Use commas to set off nouns used as direct address
Mistake: John I need you to pick up Sarah.