Why is it bad to exclusively rely on plot twists to create tension? I was told that some novice writers often make that mistake, but I am not sure why it is considered a mistake. Why is that the case? What are other means to create tension other than plot twists in your story?
The problem is that poorly done (and even many well done) twists come across as a lazy solution. The author works the characters into a bad spot, then - surprise! - saved by the twist. It also works the other way, with the characters accomplishing some goal then - surprise! - crushed by the twist and forced to start over again.
Another problem with twists is that once you've read them there's no tension anymore - hence the modern obsession with "spoilers." If all your story has going for it is that one moment of surprise, then any revelation about the story will ruin the twist and make the story boring. It also makes it unlikely that anyone will read your story again - it has nothing but a twist, and once you know it there's no point in re-reading it.
A good story lives on a lot of things:
- Interesting characters
- Interesting places
- Interesting events
- Character development
- World development
- Interactions between characters, events, and the world they take place in
- Something the author wishes to express in the story
That last point is something that many authors seem to not understand. It is not enough to tell stories about strange people and places. World building alone is a boring read.
A good story includes things that the author wants you to think about.
Those may be things the author wants you to agree with - say, a science fiction novel depicting a post apocalypse world caused by man-made pollution as an argument for better control of waste and pollution.
It may be an argument for (or against) the death penalty in a story about a murder trial.
It may be nothing more than a presentation of contentment in a slice of life story.
Whatever it is, it has to be more than "hey, look at this wild world and the strange people I made up." It has to be more than "I wrote a story for people to read because I want to be a famous author."
Any good story has points that it is trying to express. A good author puts them in on purpose and works them into the narrative. A lucky author weaves them in accidentally, then wonders why the story is so well liked. A bad author pumps out pointless stories and wonders why they are poorly received despite having all the supposed earmarks of a good story.
Forget all the places and events and magic (or technology) in your story, and ask yourself what your story is about. If you don't know then it is very unlikely that you will write a really good story.
All the events and people and places and things are a vehicle to carry some important thought from the author to the reader. Without that one thing, all the other elements (including twists) are just pointless anecdotes scarcely worth the paper (or electrons) they are written on.
Plot twists are almost always part of 'the outer journey.' The plot is the sequence of events, after all, which is external to character. For something like an RPG, the outer journey is pretty much the whole story, and so a sequence of twists in order to build tension might be all right.
But in novels, there are also characters with inner journeys. The characters change, they evolve, they grow, they move. This is a balancing source of tension.
Outer tension and inner tension work well together.
Additionally, you can create external tension through other mechanisms besides plot twists, and doing so will elevate your writing by making it more complex. A quick example of adding tension would be to use a 'ticking time bomb.' This is not a plot twist at all, but a deadline that must be met. The audience is aware that the clock is ticking down, and the audience grows more tense wondering if the hero will beat the clock.
Good luck with your writing.