I ran into this:
...For fun, the next time someone corrects you and says "That's a simile, not a metaphor," you can respond by letting them know a simile is a type of metaphor, just like sarcasm is a type of irony. Resist the urge to be sarcastic in your delivery.Nice.
Okay, so most people can tell you that to write a good simile, you first have to know a simile starts with "like" or "as." But then what?
1) Cliches do not make effective similes, as such. If a cliche is exactly what you need*, then a simile with a cliche in it is appropriate. Otherwise, no.
The purpose of a simile (as with all metaphors) is to bring to light a hidden, unknown, or unappreciated quality. Because a cliche is an overused and therefore well-known phrase, it can't do the job, by definition.
"She fled like a bat out of hell" is meaningless. Try: "She disappeared like a good night's sleep after the birth of a first child."
2) Figure out exactly what aspect of the situation you're trying to bring to light.
If your heroine is fleeing a bad guy in a straightforward suspense story, "She disappeared like a good night's sleep after the birth of a first child" is inappropriate. "She trampled the old woman like a gazelle stampeding over its wounded dam, leaving her for the lions to devour."
A simile should impress the reader visually and/or viscerally (i.e., grabbing the guts). You don't want your reader to be thinking about their kids instead of the possibility your heroine isn't as nice a person as she would like everyone to think.
3) Your simile has to have an appropriate distance from its subject. How different is the thing itself from the thing you're comparing it to?
In "She trampled the old woman like a gazelle stampeding over its wounded dam, leaving her for the lions to devour," the subject, a woman, differs from the referent, a gazelle, significantly.
In "She ran like a woman in a nightmare," the subject, a woman, differs very little from the referent, a woman in a nightmare.
In "She ran like a shooting star," the subject, a woman, differs so significantly from the referent, a shooting star, that we have trouble seeing the connection.
The simile has to walk a middle ground between too much and too little difference between the subject and referent.
Similes both have to be different (i.e., not the exact same thing) and similar (it's called a simile!). --This may seem like a pretty obvious point, but it's something I run into a lot (although not necessarily in this case).
Another point to bring up here is extremely dissimilar similes can be used help build a surreal effect. "She shot across the highway like a shooting star, her silk dress burning white into my retinas long after my headlights passed her." A straightforward, plain-speaking, salt-of-the-earth character (or narrator) is never going to think something like this. A character with head trauma, a mental illness, or writerly tendencies? Sure.
4) Your simile has to have an appropriate distance from the reader. This distance is not the same thing as the distance between the subject and referent; this is how immediate (i.e., without anything intervening) or visceral versus how intellectual or ironic you make the simile. The appropriate distance depends on how much you want the reader to see the narrator behind the curtain.
"She trampled the old woman like a gazelle stampeding over its wounded dam, leaving her for the lions to devour" is more immediate/visceral than "She ran like a deflowered virgin in a horror movie."
To put the reader in the middle of the action, use a more immediate or visceral simile. To make the reader step back from the situation, use a more intellectual or ironic simile--possibly even a cliche.
Not only do you have to figure out exactly what aspect of the situation you want to reveal and how close you want the subject to the referent, you have to figure out whether you want the reader to question the narrator.
If you want the reader to say things like, "This narrator is a very close, faithful observer, and I can trust her," then make the similes more immediate and/or visceral. "She trampled the old woman like a gazelle stampeding over its wounded dam, leaving her for the lions to devour" belongs in a book with lots of adventure. --You don't trust the character, but you do have more trust for the narrator than with "She ran like a deflowered virgin in a horror movie."
In the first simile, the narrator is criticizing the character. The narrator seems to be speaking to the reader with the simple agenda of convincing the reader the character isn't all that nice. The distance between the reader and narrator is small, as if the two of you were sitting over a bistro table and talking. "No! She didn't!" says the reader. "Yep. And then..." says the narrator.
In the second, the narrator is making fun of the character's helplessness, and, if you think about it, criticizes the reader by implying the reader is someone who likes to laugh at women who are fleeing for their lives. A complicated agenda, with more distance. The narrator is up on stage, with the garish face paint of a commedia dell'arte player, walking down to the reader in the audience from time to time and totally creeping her out.
--Keep in mind, a simile is never perfectly immediate. Action is immediate; everything else has distance. Between similes and (non-simile) metaphors, I'd say the metaphor is more immediate. "She shot across the highway like a shooting star, her silk dress burning white into my retinas long after my headlights passed her" is further away than "She shot across the highway, a shooting star..." because you're not saying the woman is like a star, she is one. Also, "like a" is two extra words of separation between the reader and your point.
5) Sometimes, you should ditch the simile and go for something else.
Similes never advance the plot. As it turns out, plot is made up of action, and only action can advance the plot. Any time you do something that doesn't advance the plot, you cost your reader time and therefore interest.
Description (including similes), forshadowing, tone, mood, theme, and backstory are a waste of time, unless you do something with them that's at least as valuable as the action you just put off. Most of these elements, when used well, tell the reader something about the story that makes the plot an inevitable juggernaut. "She trampled the old woman like a gazelle stampeding over its wounded dam, leaving her for the lions to devour" gives the reader a hint about the character that affects the plot later on--without the simile, the reader might have thought the act was an accident. The simile sets up an expectation.
"She ran like a bat out of hell" sets up the expectation that the reader will put the book back on the shelf. "She ran," at least, gets to the point and lets the next thing happen.
*You need a cliche if the line is delivered by a character (or narrator) who is making fun of someone who uses cliches (possibly himself), trying to pretend he's dumb enough to speak in cliches, is so distressed he's unable to speak in anything but cliches, or generally lacks the ability to say what he means. You don't need a cliche if you're just writing something the reader could come up with just as easily as you can.