Further guidance for my students, who are struggling with the technical aspects of dialogue, though they might not know it.
Where to put those tags
Dialogue is often better broken up with dialogue tags than ended with them. That is, there’s something more natural about: “I’m so happy,” she said. “Let’s do something about it.” Than this: “I’m so happy. Let’s do something about it,” she said. Okay, maybe that’s not a great example–but you’ll see some good examples (of how NOT to do it) is each other’s work.
Also about dialogue: be sparing with adverbs (be sparing with adverbs in general; often an excess of adverbs means that your language isn’t accomplishing what it should–many good verbs, for instance, will obviate the need of an adverb). Don’t get me wrong. I’m not one of those anti-adverb freaks. Just be sure your writing is made better and clearer with the use of them.
Dialogue AGAIN (though again there are some other applications): I can’t really think of how to put this as a rule, but here’s an example of punctuation done wrong, then right: “I’m so happy.” She said. “Let’s do something about it.” (That’s wrong. Here’s right.) “I’m so happy,” she said. “Let’s do something about it.” There are a number of places in your work this time around where this mistake is made. Also, if, for instance, we began with the 2nd part of this, i.e., “she” is saying a complete sentence, her quotation is capitalized (as in the correct version above). But if it’s one quotation divided by a dialogue tag, it’s treated as an interrupted sentence, no capital on the second part. E.g., “I’m so happy,” she said, “and I’m not going anywhere.”