Nothing marks a beginning fiction writer faster than improperly punctuated dialogue. Because most academic papers do not use dialogue, many students don't learn the proper dialogue punctuation and grammar until taking a fiction writing class.

The Dialogue Punctuation Rules

Get ahead of the game! Learn these rules, and you'll avoid obvious mistakes:Use a comma between the dialogue and the tag line (the words used to identify the speaker: "he said/she said"):

"I would like to go to the beach this weekend," she told him as they left the apartment.

Periods and commas go inside the quotation marks in American writing (the Brits have slightly different rules); other punctuation -- semicolons, question marks, dashes, and exclamation points -- goes outside unless it directly pertains to the material within the quotes, as in this example from Raymond Carver's short story "Where I'm Calling From":

"I don't want any stupid cake," says the guy who goes to Europe and the Middle East. "Where's the champagne?" he says, and laughs.

In the next example, the question mark goes outside the quotation marks because it is not part of the material being quoted:

Did he say, "We should all go to the movies"?

Also note that the sentence ends with only one mark of punctuation: the question mark. In general, don't use double punctuation marks, but go with the stronger punctuation. (Question marks and exclamation points are stronger than commas and periods. Think of it as a game of Rock, Paper, Scissors, if it helps.)

When a tag line interrupts a sentence, it should be set off by commas. Note that the first letter of the second half of the sentence is in lower case, as in this example from Flannery O'Connor's story "Greenleaf":

"That is," Wesley said, "that neither you nor me is her boy..."

To signal a quotation within a quotation, use single quotes:

"Have you read 'Hills Like White Elephants' yet?" he asked her.

For interior dialogue, italics are appropriate, just be consistent.
 

Did I forget to do my homework? he thought. 

If a quotation spills out over more than one paragraph, don't use end quotes at the close of the first paragraph. Use them only when a character is done speaking. 

"...and in the end I didn't even love her. 
I did think of marrying her, though." 

Common Punctuation Dialogue Mistakes

Incorrect dialogue punctuation and formatting is very common amongst beginning fiction writers. The most common mistake is the use quotations outside of the spoken word. Remember: only the words that the person says should be inside the quotation. But here are two more common dialogue mistakes to avoid.

Punctuation and Spacing

Incorrect: 

"Surely she has gone mad" ! she said. 

Correct:

"Surely she has gone mad!" she said. 

Commas Between Two Sentences of Dialogue

Another way that people incorrectly write dialogue is by putting a comma between two sentences instead of a period.

Incorrect: 

"I have made up my mind," she said nodding, "I do not want to marry him." 

Correct:

"I have made up my mind," she said, nodding. "I do not want to marry him." 

While you may be tempted to believe that the first example is correct, remember that two spoken sentences are still two separate sentences and need a period.