First bit of advice. All major scenes lead to the end. Some authors say they don't know the end when they begin writing their story. Not necessarily so. The end is known, depending on the genre chosen. Romances end with either happily ever after or happy for now. mysteries end with the mystery, crime, murder being solved. The list could go on and on taking each genre. An author knows the ending of their book. They may not know the exact scene but they know how the book should end. But the ending scenes aren't what's under discussion at present.
These are the middle scenes -- Discoveries, crisis, and black moment.There may be a number of discovery scenes and a number of crises. As for the black moment, there is usually one belonging to the character who has the most to lose or who gains the most. There can be two or more if the story has a number of characters who have something to lose or gain.
When writing one of these scenes remember there is a beginning, a middle, an end and a pointing to the next major scene. Often these scenes lead from a discovery to a crisis to another discovery until the story builds to the black moment or moments if more than one character has one. There are, maybe not rules, but expectations when a major scene approaches.
The first is do not wimp out. The story is going to stand or fall on these scenes. Glossing over the scene cheats the reader. Sure it's easy to put this in a bit of narrative but to keep the reader engaged the writer needs to show the act of discovery, the crisis provoked by the discovery and the all important dark moment when the character believes they have lost. So wimping out is not allowed since this will lose readers.