How to Write Red Herrings
A red herring has to tread a very fine line: it has to be visible enough that most readers will pick up on it. If the clue is too subtle, no one will notice it and it will not succeed in misdirecting the reader. This is what happened with the Watchmen example that we saw in Section 2: the brown sweater was such a subtle clue that most readers didn’t even pick up on it. At the same time, a red herring has to be subtle enough to be believable. If it’s too obvious, then readers will suspect that they are being misled, and will not fall for the trick.
In addition to finding the balance between subtlety and visibility, a good red herring has to emerge naturally from the plot. Take another look at the TV Tropes example from Section 2: the husband’s infidelity is a red herring, but it’s not random. It has everything to do with the story, it’s just that the readers are being encouraged to misinterpret it. If the red herring is just a complete tangent, with no organic relationship to the story as a whole, then readers will feel that they have been cheated.
When to Use Red Herrings
Obviously, red herrings have no place in formal essays (in fact, they are a terrible rhetorical mistake if your goal is to persuade)! They only work when the motivating factor for readers is mystery, which is often the case with novels and short stories, but not essays.