Consider your source material. Ask yourself whether you're quoting dialog from a play or a different kind of text. The type of publication will affect the format of your citation.
Look at the length of your quotation. Parts of plays and narratives take on a long citation style if they exceed four typed lines. Quotations shorter than this maximum generally use the short format.
Use double and single quotation marks for short excerpts from all texts other than plays. You have to follow a separate set of rules for dramatic dialog. Use a double quotation mark to open the quotation and a single quotation mark whenever a character speaks. For example: "Mark looked for a long time at Lisa. 'I don't know,' he said softly." For a quotation where the character starts speaking right away: " 'I don't know,' said Mark softly." Include the name of the author and the page number at the end of the quotation, placing punctuation after it. " 'I don't know,' said Mark softly" (Jones 389).
Use double quotation marks only for non-dramatic dialog that takes the long quotation format. Indent the entire block of quoted text one inch from the margin. Don't use any quotation marks to introduce the excerpt; just use double quotation marks to signal that a character is speaking. Use the same parenthetical reference format, but place punctuation immediately after the quotation ends instead of after the closing bracket. For example: ...and I don't know what to do," he said. (Jones 487)
Use the short quotation format for dramatic dialog if the passage is shorter than the maximum stated above and only one speaker is cited. The University of Toronto gives one example from Shakespeare's King Lear: Lear notes that "When the mind's free / The body's delicate" (Shakespeare 3.4.11-12). Indicate the act and scene in your parenthetical citation, along with the lines quoted. The example above is a passage from act 3, scene 4, lines 11 to 12. The / punctuation indicates a line break in the original text.
Use the long quotation format for both longer dramatic passages and those with more than one speaker, regardless of their length. Block indent the excerpt one inch from the margin. Include speakers' names in capital letters, followed by a period. Each time a new character begins talking, start a new line and indent the spoken text one inch from the end of the new speaker's name. Do not use quotation marks. Use the same style of parenthetical citation as you use for short dramatic quotations, but place the punctuation at the end of quoted passage instead of after the closing bracket.