Quotation marks
Quotation marks are used most often with dialogue. They can be used for some other purposes, but this should be done sparingly. Quotation marks are not used to indicate thought. The exception would be when characters communicate telepathically, in which case a combination of italics (indicating the words are thought and not spoken) and quotation marks (indicating speech between characters) is used.

Commas and periods (when appropriate) are always placed inside the closing quotation mark. Question marks and exclamation marks go inside the closing quotation mark when they are part of the quoted material; however, they are placed outside of the closing quotation mark when they refer to the surrounding sentence rather than the material in quotes.

Usage
1. Direct quotations

Example 1: “I want cheesecake,” Sylva said.
Example 2: Sylva said, “I want cheesecake.”
Example 3: Can I have cheesecake?” Sylva asked.
Example 4: Sylva asked, “Can I have cheesecake?”
Example 5: “Oh my God, cheesecake!” Sylva screamed.
Example 6: Sylva screamed, “Oh my God, cheesecake!”
Example 7: “I think”—Sylva opened the box—”we should have cheesecake.” (Narrative interruption)
Example 8: “I think,” Sylva said, “we should have cheesecake.” (Attributive interruption)

2. To indicate irony

Example: His “medicine” made her sicker. (Exception: do not use quotes if preceded by “so-called” or “namely”)

3. To indicate a word used questionably or with meaning beyond the denotation

Example: Darlene arrived with her “friend.”

4. Can be used in place of italics to indicate word used as a word, instead of what it usually references (or a letter)

Example 1: The word “book” has four letters.
Example 2: Is there an “E” or an “I” in “bistro”?

Exceptions
1. When question marks and exclamation points refer to the surrounding sentence rather than the material in quotes, the question mark and exclamation point go outside the closing quotation mark.

Example: Are you attending the seminar titled “Punctuation—What, Where, When, Why, and How to Use It”?

2. Quotation marks aren’t used around indirect quotations.
Example: He said (that) he hated cheesecake.

3. Semicolons and colons, when adjacent to quotation marks, always go outside quotation marks.