Knowing Your Audience
When you go to a social event, it helps to be able to read the room. You can see the reaction of the people you’re talking to, shifting topics to hold their interest and adapting along the way. But you can’t do that with writing. What’s on the page is what readers are going to get, and one group of readers may react very differently to the work than another would. The typical example of this is romance readers — if your story doesn’t leave your characters with a happily ever after, or at least a happy enough for now ending.
But this can apply to any audience that will be drawn by your cover art or the description of your story. Say your story promises a plucky cat POV character. (I happen to be doing a presentation this fall for the Cat Writer’s Association at their conference, so I’ve been reading a lot of cat-forward stories – substitute cat with any element that will draw readers.) Readers are going to expect the cat to be doing things and making decisions in the story — even if the feline isn’t the protagonist. They will be disappointed if the cat is only a prop in the story, or if it feels like the cat mainly appears to look cute on the cover. The relationship the protagonist has with the cat is more important than if the cat wasn’t part of the blurb, because if readers feel the protagonist is neglecting the cat — or worse, has an adversarial relationship with the cat — that can push her into the realm of unlikability. For a different audience, that same relationship could read as playful or funny (if executed properly — without falling into sarcasm or meanness). But the rest of the book would have to be tailored to that audience.