There is a whole lot of advice out there on how to plot. One of the simplest guidelines is to never make anything easy on your characters. If things are going well, then the chances that the reader might be bored are pretty high. This advice has been extremely helpful for me because I have a tendency to want to protect my darling characters, let them bask in their success for a bit too long, and also to have them quickly/easily go through necessary steps to get to the next plot point. Nothing should be quick and easy though - it's either a missed opportunity to make the character's life just a bit more difficult (and thereby raise the stakes, show character growth, etc.) or it's something that needs to be cut.
At first, I took this advice for face-value and had my characters always take the rockier road or make the more difficult choice. But then, I realized that everything they did was totally predictable. The reader basically knew from the get-go that these characters were always going to run into the worst possible situation. And when a story is predictable, it can be boring. So there I was, back at potentially bored readers.
That was when I realized that putting my characters into tough situations wasn't enough. I needed to make sure that the tough situations were the result of something unexpected. And even better if I could make the reader think they knew where the story was headed, think they could anticipate the next plot twist, and then rip the rug right out from under their feet! That might not sound that difficult, but in reality, I can be far less clever than I think I am. With one of my CPs, we critiqued one chapter at a time and wrote down our predictions for the next chapters. And I couldn't believe she knew (or didn't know, in some cases) where my story was headed.
What about you? How do you make sure your MS doesn't become too predictable? Do you have an tips or tricks for creating unexpected plot twists?