What is the best way to break up dialogue when writing?

Read some Michael Cunningham. He does good dialogue.

Imitation, as @cazzie says, is the sincerest form of flattery.

Pick a style/format that suits you and stick with it. Honestly, there’s no better advice than that. There are too many variables for anyone to give you a definitive answer to your question: type of novel, number of characters, etc.

If it’s a romance where the important dialogue basically relates the interaction between two characters, then that’s obviously going to take a different style than, say, an Ocean’s Eleven story with multiple important characters and lots of action/locales.

When your book is finally a success, it will have gone through many revisions and editings. The important thing right now is to pick a style you’re comfortable with and stick with it. There’s nothing wrong with imitating a successful author in the same genre to get started.

he concerned amateur.

Sometimes a simple paragraph break will work between characters provided the intro to the dialogue is descriptive enough to establish context. But it is a good idea to identify at least one of the speakers now and then in long dialogue. You don’t want to bore your reader with the unnecessary triteness of identification on every line. And allow your reader to think for themselves. They can smell pandering from a mile away.

Dolan and Blaine were casing the area in the ramp-up to the heist. Dolan was driving and looked nervous. Blaine hated Dolan’s guts. He didn’t like the idea that this amateur punk was in on the heist, much less at the wheel. If it wasn’t for his fucking uncle financing the whole deal, he wouldn’t even be here. Here they were in the preliminaries and he was already sweating like a nun in a cucumber field. Maybe it was time to have a little fun with this asshole.

Blaine looked over at him from the shotgun seat and grinned. “Sometimes adrenaline gives people the shakes, some might think it’s cowardice, so maybe you’d want to pray about it.”

Dolan looked surprised that Blaine would even speak to him. “I’m not a religious man.”

“Hey, there’s nothing wrong with prayer, man. Back in Nam we had this kid, this Bible-beater. Volunteered for point on every mission. He always carried a bible next to his heart. We used to fuck with him about, but that bible stopped a bullet.”

Dolan kept his eyes on the road, but Blaine had his interest. “No shit.”

Blaine had the little dumbass now. “Hand of God, that bible stopped a bullet. It would of ruined that fucker’s heart. And had he had another bible in front of his face, that man would be alive today.”

“Fuck you, Blaine.”
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You’ll notice that ”, he said.” is used. If the context is well defined, that can be kept to a minimum.

^^edit. You’ll notice that “he said” is never used.

Excellent advice from you all. I really appreciate it.

Compare and contrast:

“It’s getting warm in here,” said John, as he turned around and unbuttoned his overcoat.

Versus:

John turned around and unbuttoned his overcoat. “It’s getting warm in here!”

There are many ways. Read some competent authors and choose a style that works for you. There are also tons of books and thousands of web pages devoted to the craft of writing.

(I believe you meant “immature,” not “armature,” which is a component of electrical devices. Care in your delivery is important for a writer. If I were your editor I would have to make at least six corrections in your question details.)

Personally, I dislike reading those dialogues that dispense with quotation marks and those that stretch and strain to come up with a hundred alternatives to “said.” She asserted, declared, giggled, taunted. He averred, snarled, trumpeted, murmured. Egad. Use dialogue beats as @Espiritus_Corvus explained, and when the speaker needs to be named, just use “said.” It’s practically invisible to the reader, who just gets the necessary information from it without distraction.

I read a lot (typically more than 500 pages a week), and I actively dislike these things in dialogue:

• lack of quotation marks (sometimes replaced by dashes, italics, and other typographic tricks)

• long exchanges without tags, where I lose track of who’s speaking and have to go back and count alternating lines; sometimes I even have to pencil in the characters’ initials

• too many adverbs: he said eagerly, caustically, threateningly, smilingly

• overdone dialect

• use of some repetitive phrase to identify a character, as if that passed for characterization; for example, one who prefaces half of her utterances with “Oh, my word” or routinely calls everyone “darling”

• inconsistent use of names for a character; for example, if the author calls him sometimes “Bobby” and sometimes “Smith,” I could be well along before I realize that “Bobby Smith” is a single character. Some authors do such thorough sketches and bios of their characters—even the minor ones—that they may forget what they’ve told us; and then suddenly they’re referring to “the woman from Denver” and they don’t realize they’ve never actually mentioned her origins before.

I could go on, but really the best advice for a writer has always been and still is “Read, read, read.”

I would add, “Read attentively and thoughtfully.”

“Overdone dialect,”

Word. GA