For many genres, it’s important to hook readers’ attentions in the beginning.
A lot of authors will do this with action, violence, sex and gore. Visceral, tactile experiences communicating horror and mayhem for shock value. This can be effective, in theory.
The problem is: where does it go from here?
Firstly, nobody gives a shit about your characters in the beginning. You have to make readers like them first, and that takes time. But you can’t take too much time; you have to hint that something exciting is coming, and that the stakes will be high.
So starting with a death in the preface/first chapter is generally a good idea.
But then you need to slow way the fuck down. Your beginning needs to contrast with the ending. You need a nice, stable ordinary world – the pot of water has to be cold. The characters relaxed.
Then you can turn on the heat. Add some salt and spice.
Bring it to a simmer.
Now your characters are freaking out a bit. They know what the stakes are. They know what’s expected of them.
But they probably resist. They shouldn’t want the violence that’s coming. They should try to avoid it. They also don’t want to become badass ninja fighters who slaughter hordes of faceless bad guys.
They should resist being special, being chosen.
A lot of indie authors screw this up, by starting off with a special, powerful, magic supersexy protagonist who can smote the shit out of everyone. But remember, even when the protagonist finally commits to her path, when she accidentally or is forced to make her first kill (or metaphorical kill – the first conscious and deliberate action that moves the plot forward, which she’s been resisting until now) she’s still going to fail.
She needs to fail, again and again. Especially right before the beginning of Act III.
Very probably, somebody she cares about dies, too. But it matters much more than the meaningless death(s) in the beginning; because it’s her fault somehow.
In the beginning, a few people died – or just one – probably a necessary evil and the beginning of the antagonist’s evil machinations. So she got involved; resisted at first, but then committed.
And now, because of her actions, more people are dead. So she questions herself. She feels responsible. And if feels terrible.
So she’s probably going to give up, until an ally talks her into getting back on her feet, even though hope seems lost.
Then, finally, you unleash all of her most amazing, super effective, incredible baddass ninja-warlock-fae powers.
The point is, don’t use up all your tricks
If you start in the beginning with rape, murder, dungeons and blood, bones breaking, pregnancies, vampires and werewolves and lost princess descendants (I just sampled an indie book that started just this way; prompting me to write this post) you won’t have hooked readers, you’ll have bored them. OK, now we’ve seen everything and know what to expect. Why keep reading?
You need to hint. You need to show some blood and gore (and/or sex), but not why it matters, who caused it, or how it relates to the main character. Not yet. Your hook has to leave the reader with questions, and make him care about the answers.