Details are what makes a novel. But they can also be what drags things down. A good novel finds the right mix between too much detail and just enough.
I’ve found this can be a problem especially in the fantasy genre. There’s a lot of world-building that goes into creating an entirely new world with new rules and systems of government and things, and all of that can be incredibly interesting to create, but for readers, it can bog them down in unnecessary details. How do you integrate those in, then, without boring anyone? After all, Tolkien goes on for three pages about mountains, so what’s a few paragraphs about a magical tree? Well, Tolkien was basically the first, so he got away with it. Us? Not so much.
Most of the world-building and even character-building for other genres never makes it into the book. You may know your characters favorite color and childhood traumas, but your readers may never find it out. It may never come into play within the text of your story. It’s still good to know these things as it helps create a more well-rounded character or richer setting, but you don’t have to tell everyone everything.
Details can trip people up if they get stuck in the bog, but you have to learn to find your own balance. If you’re unsure, have someone else read your work specifically for details. You may find you have too many or not enough. Especially in general fiction, it can be easy to leave out the details and just assume that your readers know what things look like or feel like. The point is immerse your reader into whatever world your writing, whether it be something set in present-day or a hundred years from now. Don’t assume anything about your readers except that they like to read. That’s really all you can know about them. The rest, you have to show them and that’s up to you.