I'm looking for interesting ways of breaking up some of the longer dialogue exchanges in the novel I'm working on. If two or more people are simply standing in one place and talking for an extended period, I don't feel like I have a lot of non-dialogue options beyond delving into the characters' thought processes and bodily mannerisms. But I don't want to lose the reader in a sea of dialogue. Ideas?
Make it as interesting as possible and cut away everything that is not necessary / advance the story/character/add suspence. In short, don't make them chat about the weather and other unimportant stuff for 6 pages if the essence comes in the end of the fourth page.
What Tesoro said, and check if you are info dumping in the dialogues. If everything mentioned is checked and involves interesting dialogue subtext, I don't mind long dialogue exchanges.
Pare down the content to get rid of fluff. Use beats often to reduce the number of dialogue tags needed, and to repeatedly anchor the dialogue to the setting. See He said, she said - Mechanics of Dialogue if you are unfamiliar with beats. Interrupt lengthy exposition at the most interesting points. Not only does this break the long dialogue into more palatable pieces, it builds anticipation in the reader. Try to find a story called Vegetable Matters by site member Terry Ervin II for an excellent example.
even if the speakers are standing still, they're still doing something... they're reacting in some way to what the other is saying, fidgeting, or looking here and there, and so on... so give the readers a visual connection to the scene, too, and not just the chit-chat... insert these bits in appropriate parts of the dialog and it won't be so boring...
Also, you can insert small intrusions of the outside world into the scene: say they are sitting in a park at a picnic table, then as Cogito says, at a high point of interest in their dialogue have one of them notice: Two ants in a tug-of-war over a bread crumb. Or a low flying airplane roars over head. A distressed old lady clutching a dog leash asks if they saw her puddle fluffy. Or have a frizbee bounce off the head of the speaker...whatever. Just as this set-up anticipation in reader, it also allows them to pause and reflect upon what has been said up to this point.
You need to "show" only the important dialogue. Filler dialogue (or actions) can simply be referred to briefly, spelling out that they spoke about (or did) this and that and then resume the important dialogue.
You could have one of the character's participating in a hobby of some sort while the conversation went on. One could be sculpting a statue of Mickey Mouse, he could be painting a picture of Mickey Mouse, making Mickey Mouse shaped pancakes or any number of Mickey Mouse related activities.
He'd better be careful, Nick. The Disney company takes a dim view of people making unauthorized images of their characters, and they have battalions of big, strong lawyers. On the other hand, if Mickey Mouse were sculpting the character as the conversation went on, that might be rather surreal.