Honoring the hotspots in a story means allowing them to explode into scenes. Dialogue is another word for the fireworks that ensue.
New writers tend to regard dialogue as a forbidding mystery. Capturing life on the page will always feel a bit mysterious, but in the case of dialogue, it opens up with one simple key: need. Dialogue happens when one character needs something from another, and at the same time, that other resists giving it. And vice versa. The something at stake can be an article of clothing, money, food, the car. But it can also be intangible, like information, approval, love, even abuse! Two characters may need their differing versions of an event to be accepted as “right.”
This underlying need is called subtext. It’s the reason why the characters are talking. In fact what distinguishes the characters in written narrative from real people is that their buried selves gradually come unburied. In real life, we “make conversation” in order to fill up silence and facilitate casual encounters. We follow the conventions of polite behavior. We don’t usually answer the question, “How are you?” honestly. In many cases it’s wise to keep our buried selves buried. But if your characters are doing that, you must poke them until they begin to poke at each other.
Think about the potential subtext that might underlie a question like, “Could we meet on Sunday instead of Saturday?” Imagine the verbal tug-of-war it might incite. Or what if a character chose to answer one of those conventional questions unconventionally?
Crafting strong dialogue means generating a lot of material, maybe three times more than you will wind up selecting for the final draft. Let A stand for one character, B for another, then work your way down the page letting them alternate talking about and around the “hot” subject. When the first burst of interchanges slows to a halt, don’t let them off the hook. Have one of them say something you would never say, and get the stream flowing again. Keep them talking until some of the things they blurt surprise you.