Some estimates suggest that one out of every 25 words we encounter is a metaphor. When writing, you’ll find yourself writing metaphor subconsciously as well as consciously. One pass of editing should focus on imagery, to nix accidental, not-so-great metaphors.
Metaphors are privileged areas for lying: by granting authors these limited flights of fancy, readers kid themselves into believing that what is not figurative in a text is somehow ‘truer’.
– Jason K. Friedman in Goth: Undead Subculture
Example: Good Metaphor
From Up the Mountain Coming Down Slowly (by Dave Eggers), set in Tanzania:
A woman on the tour bus has ‘leonine hair, frayed and thick, blond and white’.
Tanzania = lions = good metaphor because it reflects the setting.
Here’s another from Revolutionary Road (Richard Yates), describing Frank’s place of work:
At first glance, all the upper floors of the Knox Building looked alike. Each was a big open room, ablaze with fluorescent ceiling lights, that had been divided into a maze of aisles and cubicles by shoulder-high partitions. The upper panels of these dividers, waist to shoulder, were made of thick unframed plate glass that was slightly corrugated to achieve a blue-white semi-transparency; and the overall effect of this, to a man getting off the elevator and looking across the room, was that of the wide indoor lake in which swimmers far and near were moving, some making steady headway, others treading water, some seen in the act of breaking to the surface or going under, and many submerged, their faces loosened into wavering pink blurs as they drowned at their desks.
There are several different metaphors in the paragraph above (fire and mazes included), though those first metaphors don’t really jump out because they have become a part of the language. (‘A maze of corridors’ has become cliche – though we shouldn’t despise the cliche too much – it gets its meaning across.)
The extended metaphor of the sea of swimmers is particularly well done because, although I’ve seen similar open-plan offices in my life, I had never made the connection that the workers in such an office are like swimmers. When Yates describes how each is at a different stage of submersion, I think, ‘Yes, that’s exactly how it looks’.
But the true brilliance of this extended metaphor is how it relates to the theme. Frank Wheeler’s mediocre suburban life is itself a form of slow drowning, even though at first glance, this cruisy job feels like a day at the beach.
The Sea = Frank Wheeler’s Workplace = A slow drowning disguised as a harmless environment = A very good metaphor because it echoes the theme.
Example: Bad Metaphor
Perpetrator: me, some years ago.
My story was set in contemporary New Zealand. High school students are in a car, making their way to a school ball. Comment below comes courtesy of a writing group critter:
Streetlamps flash-danced by,  and neon signs and traffic lights and ordinary people making their way to ordinary places. Why couldn’t everyone have this much fun, every night, everywhere?
[l1]Nice echo of Katherine Mansfield here, but I’m not sure of the purpose of it.
Exactly. There was no good reason to include ‘flashdance’ in a contemporary story for young adults. Not when the setting is New Zealand. Not when flash-dancing should get the reader humming ‘What a feeling!’, if anything at all.
Flashdance = America = 1980s = bad metaphor. I took it out.
Drag it Out: How to Use Extended Metaphors for Maximum Effect from Lit Reactor