One of the most important parts of writing good dialogue is its' punctuation. Poor punctuation of dialogue leaves a reader confused and frustrated. There are few things more frustrating than having to go back to the beginning of a conversation in a book and try to work out who is speaking at the end of it, except perhaps coming across an unattributed remark in the middle of a page.
The first rule of dialogue is that everything a person says goes between quotation marks, "like this." This can be broken up if necessary, but make it clear whats going on. For example, " Stop," he called, gasping for breath, " stop right there." Whether to use double or single quotation marks is largely a matter of taste, but quotes within speech should be enclosed in the oppposite type to the direct speech. For example, " I was so insulted, he said 'hell hath no fury' and laughed at me."
The second rule is that each time a new person speaks they get a new line, for example,
"Stop," he called, gasping for breath, " stop right there."
"No, catch me if you can."
Every line doesn't need to be attributed, and every line doesn't need an adverb to describe it. In fact that can irritating. Good dialogue shows you how something is being said, without the writer needing to tell you.
For example, "Where is it?" is obviously a question, it doesn't need "he asked" after it to make that clear. In fact the extra words break the natural flow of the words.
When conversations last for a while they should flow and it should be easy to tell who is talking, with just the occasional note from the writer to allow the reader to keep up. Read back through dialogue you have written and make sure it is clear who is speaking. Better yet get someone else to do it for you.
The punctuation around the dialogue itself usually causes more problems for writers. When using a phrase to introduce speech separate the speech from the phrase with a comma. For example, he ran up to me and shouted, " Did you see that, did you?"
Punctuation of the actual words spoken should reflect the speech, check that it sounds right by reading it out loud. Writers often use puntuation to try and convey accents, as in G'day. Careful here, only do it if you are sure of how the words should sound, and the punctuation makes them sound that way. Just leave the words alone if you can't do the punctuation successfully.
Punctuation at the end of speech can be more problematical. There are two styles. The American style places all punctuation inside the quotation marks regardless of context. The English style moves punctuation according to context. If you are not familiar with the English style don't try and copy it, you will get confused and then confuse your reader. In our global community both styles are acceptable to people who care about the details.
Good dialogue only requires full stops, commas, question marks and the occasional exclamation mark at the end of a phrase. Commas are used when an attributive phrase follows, for example, " I'm going now," he stated. Full stops finish speech, obviously, and question marks form a question. Exclamation marks should be used sparingly. Do you know any-one who talks in exclamations! Do you?
Once you have written your dialogue go back over it. As each new person speaks did you start a new line? Is it clear who is speaking? If a person speaks more than once or more than two people are talking is it clear who says what? When each person finishes speaking is there a full stop or question mark? Can you tell the mood of the conversation from the speech? If you answered yes to these questions you probably have the punctuation right.