This is an exercise that I completed recently and it is taken from the book "The Discovery of Poetry" by Frances Mayes. The task is to think of similes or metaphors that are unusual or surprising, ones that you may have never seen in print before, by completing phrases provided by the author. Here is my attempt.
The moon, broken off like...an unfinished symphony
A red flower, brilliant as...a strumpet's gown
Her fingers, delicate as...paint spatters
The island stretches out from the coast like...a stiletto heel
Your backbone ridged like...an unfinished metal edge
Soft as...chocolate swirls
That bicyclist, careening downhill like...Icarus' dripping wax wings
Crazy bird! Its song like...raw lemons
His monotonous voice like...sticky caramel chews
She spun off like...a maypole dancer
Days pass like...amber gems in sunlight
If you are interested at all in writing, this is a great exercise. There is no need to limit yourself to single line descriptions. I did this exercise with my writing group and some members did more lengthy descriptions that could actually be worked into short stories.