A plot twist in a mystery is simply an unexpected occurrence. When writing your story ask yourself what you might write that your reader would not expect.
Then give your reader
- more than one suspect in a murder case before revealing the true culprit.
- red herrings and dead ends.
- important clues buried in emotion or action scenes.
- a hero who uses a special skill to extricate himself from a terrible situation. A skill mentioned in passing earlier in the story.
- a villain who has some traits that enable him to turn heroic.
- trusted characters who lie.
- a main character who thinks he’s won the battle but discovers later in the story that he hasn’t or that the win has endangered someone he cares about. Now he must continue the good fight.
- a villain who wins victory after victory until the hero is almost destroyed. Note I said almost.
- a plot that works towards a clear and easy outcome then throw up barriers that block the hero’s path to success.
Unexpected occurrences are the simplest way to create plot twists.