Class is back in session, kids. And no, an apple for the teacher will not get you higher marks. But learning the proper usage of that persnickety piece of punctuation, the comma, will help you make a great impression in all your correspondences and marketing initiatives. Everyone needs to know how to write well in order to gain the confidence of customers and colleagues.
If you have ever been in doubt when you need to use a comma, here are the simple rules for the most common applications:
1. To divide what could be two separate sentences
When writing, we often combine sentences, such as:
I went hiking in the hills, and I saw a flock of hummingbirds.
We use a comma, above, because these two sentences can stand on their own: I went hiking in the hills. I saw a flock of hummingbirds.
If the two sentences cannot stand alone, no comma is used:
I went hiking in the hills and twisted my ankle.
No comma is used here because these two pieces of information cannot be sliced into two sentences as they stand now. I went hiking in the hills is a complete sentence; twisted my ankle is not a complete sentence.
However, a clause that is dependent on the main clause does not contain a comma if it is essential to the meaning of the sentence:
I will sign the agreement if you can raise the money you promised.
2. To introduce names or professions
This is my ballet teacher, Mrs. Foot.
James Bond, 007 of the British Secret Service, has just popped ‘round for tea.
My plumber, Pat, laid the pipes in the pond.
3. Items in a series
I went shopping for carrots, bread, flour and eggs.
Note: A comma is not needed before the conjunction ‘and.’
When a sentence contains a series of short independent clauses, use commas between them, as well as before the conjunction (as in ‘and’ or ‘or.’)
I read, my sister knitted, my daughter practiced piano, and my husband made dinner.
Use semicolons instead of commas when your list of items includes longer phrases or internal punctuation:
I like playing softball; going out to soccer games; eating blueberry sorbet; flying kites; reading all day long; napping for hours; and blogging about my dog.
The children received high marks: Eliza, A-; David, A; and Henrietta, B+.
4. Introductory phrases or words
Often we start sentences with phrases or words preceded by phrases that could stand on their own. A comma in these circumstances indicates a pause. When trying to figure out whether or not you need a comma, just the simple test of reading the sentence aloud can help you determine the answer. If you naturally pause, you likely need a comma.
Oh, I love that!
Yes, please order me a glass of wine.
After having shopped for 2 hours for a briefcase, I stopped for a coffee.
I stopped for coffee is a sentence all by itself, while After having shopped for 2 hours for a briefcase is not.
Exceptions: introductory phrases that come directly in front of a verb do not need a comma. For example:
Shopping for a briefcase was all I did today.
5. Parenthetical elements
Use commas to set off phrases or words that are intentional pauses within a sentence, such as: however, indeed, therefore, and to say the least:
I like the color blue, however, the red sweater looks better on you.
You are running out of money, therefore, you should cut back and not go out to dinner.
6. Commas between adjectives
When a noun is preceded by two or more adjectives, commas normally separate the adjectives – unless the adjectives are normally paired together or considered a unit. For example:
Brad is a young, handsome guy.
I have a very long, difficult day tomorrow.
The daisy is a delicate, white, pretty smelling flower.
But:
I have a very nice friend.
There is a very high glass ceiling at this company.
7. Commas with repeated adjectives
I’m having a very, very bad hair day
Many, many people are upset with you.
Now that you know how to use commas, your communications will look cleaner and more professional – and that means more business for you and your company.

Emily Randolph, aka, the Word Nerd, is the Founder and Creative Director of WordsFlowZone.com, a marketing communication and copywriting firm. Randolph has been writing for companies internationally and domestically since 1992. She is also the co-author of Dima’s Dog School: The Foolproof New Way to Train Your Dog. She studiously puts a copy under her dogs’ beds at night hoping they will read it by osmosis.