Six Ways to Improve Dialogue
Beware Colorful Language. Too much slang and cursing can be distracting and slow the reader down.
Slang dates very fast. So you risk the dialogue becoming incomprehensible.
Cursing, while it may be accurate, reads "loud," the same way writing all caps writing will do.
Use judiciously.
2. The Backstory Burden. It is a common writing truism that backstory can hamper pacing, especially if it fails to advance the present-day plot much.
This truism applies equally to running text and to dialogue.
3. Tag Tumult. Characters can hiss, cackle, yell, shout, and whisper, but be wary of having them do so all on the same page.
While mixing up tags can create an exciting, dynamic reading experience, it can also create a sense of chaos.
Perhaps, that's why some rely solely on "said"; though all "saids" can risk being dull.
4. ♫Do speak♫ Avoid having characters react to dialogue with silence.
While such silences may be true to life, they often doesn't read well, coming across as if the character has gone catatonic or lost the ability to move their lips.
5. Avoid disconnection. Sometimes characters seem to talk past one another, not really relating to what one another said. The dialogue becomes sprawling and unmanageable.
One trick to ensure dialogue avoids this is to have a character repeat a word or phrase another character brought up.
6. Include Description. Dialogue that has little description around it scans like a play.
But with a play, you have the benefit of actors and a set.
For a book, you usually will want to describe some of these things around the dialogue.