1. Kill characters because you find it fun
Come on! You’re a writer and you enjoy this. In fact, you offer a comprehensive package: last words, cause of death, mourning, gravedigging, funeral services, and more mourning. You probably even bring the rain. This is your element but its benefits are twofold if you kill beloved characters for no plot-furthering reason. It will frustrate readers.
2. Add commentary in the author’s voice
There is no better way to make your story unbelievable than to draw readers out of the flow with your observations. If you struggle to create content for this purpose, think about writing moral lessons. Analyze your characters and comment on their decisions and attitudes. And if you really want to frustrate your readers, spiderweb away from the topic at hand. Readers hate tangents.
3. Don’t let the obvious happen
Set up a guy and a girl who are just perfect for each other. Then make one of them say “this just won’t work” and walk away. Have a cool detective investigate a murder. There is a suspect and all the evidence points to him but right in the climax reveal the detective as the murderer. Plot twists like these will ensure your content is original and will keep your readers on the edges of their seats (doing their best not to jump up and kill you).
4. Make mortals immortal but still mortals
Let me break this down. Make your regular human characters seemingly immortal but never offer an explanation for why they seem immortal, so your readers assume they are still mortal but can’t die. It works. I never find myself relating to the guy who defeats alien hordes with a spoon but never has to see the doctor. Make sure your readers don’t believe your character can die and if you can’t frustrate them, you’ll at least bore them.
5. Avoid any and all closure
This is a must have if you want readers to read to the end and be frustrated. It is even more effective when paired with #3. Do your best to raise questions, suggest future answers, and then write “the end” before you can resolve anything. This is extra frustrating when done across a series. You might not succeed in your goal with the first book, but after properly avoiding closure on the fourth or fifth book, readers will be frustrated. They will probably be suspicious of your intentions and wonder if you really have notes for the final book. In short, leave them with the same question you raised at the very beginning of the story and