Beware the dreaded –ly. Most of the times that it crops up in a dialogue tag, it has no business being there. Dialogue tags should be as inconspicuous as possible. The thing about using adverbs with your dialogue tags, is that you can usually convey the information with a more precise word. For example:
“I found the key!” he exclaimed triumphantly.
First, if you are using an exclamation point, it is redundant to say “exclaimed”. Secondly, “triumphantly” is a long one that doesn’t add a lot of meaning. Picture something doing something triumphantly. That is not a concrete picture. People show triumph in many different ways. (Lifting the key in the air “Legend of Zelda” style, dancing around, grinning and giggling…)
How would you fix it? Think about the following example.
“I found the key!” he cried, hoisting it over his head.
This way gets rid of the adverb, makes a less conspicuous dialogue tag, and creates a more concrete picture.