Conflict
To be honest, I think such things as "Every scene needs conflict" are so formulaic, so removed from the way good writers actually write novels, that following such advice can only produce really bad novels. Stories need conflict. Every story needs an ongoing conflict, and a series of minor conflicts, but to say every scene needs conflict flies in the face of many, many extremely good novels I've read. Particularly historical novels.
A scene should be there for a reason, but that reason need have nothing at all to do with conflict. I mean, read a bunch of historical novels. If you can find conflict in every scene, you see things that I don't. Read James A. Michener. A historical novel without a lot of history is like a science fiction novel with no science.
Scene length is another thing that drives me crazy. There is no size limit on scene length. A scene, like a chapter, or the novel itself, should be as long as it takes to get everything in. This may be 200 words, or it may be 2,000 words, or it may be 20,000 words, and all three are fine.
When you start trying to write a novel according to rules like "Every scene needs conflict," "each scene should be this long or that short," "each scene should have a resolution," or each scene should have a sequel," you aren't writing fiction, you're putting together a jigsaw puzzle, and I guarantee the seams between the pieces are going to show.
I seriously don't believe any good writer does this. Not even the writers who write how-to books saying you should do this. When you read their actual novels, they seldom sound anything like the advice given in the how-to book.
What is it King says about his how-to book, "I can't tell you how I do what I do. I can only tell you what I think I did, after I did it."
It's my opinion that when a writer starts micro-managing paragraphs, scenes, chapters, and anything else, the writing and the story both suffer.
Readers don't give a rat's whisker about such things, and they shouldn't. Readers want a good story, filled with good characters. And they want the story, and the characters, to be set in a real, believable world, and not a world that's micro-managed to the point where every scene is this long or that long, has this happen or that happen, where every single scene has conflict. I mean, really, give the poor reader a break. In a 2,000 word short story, the reader doesn't need time to come up for air, doesn't need time to think, to ponder, to wonder, or just to daydream. But in a novel, a reader needs all these things.
And you can't micro-manage them into the novel, either.
Giving info is not automatically an info dump. Readers need and want information, they just don't want all of it at once. That's an info dump. But a single scene that's primarily or all info does not an info dump make. If you spread the info out, it's not a dump.
And you don't have to mix conflict with the info.
I think some how-to books are incredibly valuable, but they are never the ones that diagram exactly what you should do, how you should do it, and that break novels down into jig-saw puzzle pieces. A good rule. If the book contains a chapter called "How to write a scene," dump the book.
And they are never, ever ones written by writers famous only for writing a how-to book, or famous for writing novels or stories darned few have ever heard of. Fiction just doesn't work this way. There's something incredibly wrong about a writer being famous for a how-to book, rather than being famous for the fiction he or she writes.
Read all the bestselling historical novels you can find, or bestselling novels in any genre, and I doubt you'll find many, or any, that follow such micro-managing rules.
I mean, I simply don't know a selling novelist who even thinks about such things with every scene, or even with most scenes, while actually writing.
The idea is to tell a story, not to assemble a jig-saw puzzle. And the idea is to write scenes that have a reason for existing, not scenes that always have this, that, or the other, that are this short or that long. Any reason is good enough, and darned if I'd want to read a novel of any length if I knew each and every scene was going to follow any of these "rules." The last thing I want to do is read a novel where every scene has a certain length, or a certain content, be that content action, conflict, or the word rhubarb.
I think it's natural to look for advice, for diagrams, for detail by detail breakdowns of how good novels are written, for how scenes are written, but I don't think such things really exist, and wouldn't work if they did. New writers seem to think novels are like TV pictures, made up from millions of little pixels, and you can look at each of these pixels and see how the picture was made.
Novels are more like paintings. Yes, there are brush strokes you can see. The novel does need a plot, it does need conflict, but the strokes are broad, never the same twice in a row, and and the painting is always greater than the strokes that made it. Godo novels, like good paintings, just can't be done by using a paint by the numbers kit and filling it teh little spaces according to the number.
Read novels, then write a novel. Write it the way you want to read it, not the way someone you've probably never heard of before seeing his or her how-to book says write it. Write it like the ones you've read (And this does not mean turn the one you red into pixels and try to reconstruct one just like it. It just means if you really liked that story and those character, do the same, only with yourself added.), and more, write it like the one you really, really want to read next. If you have a reason for writing a scene, then write the scene, and don't have a heart attack should it be too long, too short, or, gasp, lacks conflict.