My wife has a very simple rule when it comes to fiction: If fire could solve the problem, there has to be a good reason for the characters not to try it.
Take Sleepy Hollow. I love the show, but this week’s episode featured a serial killer who confined to a painting in between murders. The simple would see the characters take the painting, toss it in the fire place with some lighter fluid, and the episode is over by the first commercial break. Unfortunately, this isn’t what the characters did, instead going a route that required tracking down magic bullets embedded in a dead body (always leave one bullet in, no one should have to say that!) and using them to shoot the painting.
Because…shooting a painting instead of burning a painting?
Look, if there’s a simple solution to a problem, it is going to occur to the audience. Who will then wonder why it doesn’t occur to the characters. So it needs to occur to the characters and be dismissed for one reason or another. This takes two lines of dialogue, a mere blip in a story, TV episode, or movie.
It’s the simple things, it really is.