In Christopher Barzak's interesting debut novel, One for Sorrow, I came across this lovely description of an old woman's hand: "the skin on her palm was so soft it felt like it would slide right off her bones." That's exactly right. In a few specific words, Barzak captured the looseness of old flesh plus the effect it has on a youngster who touches it.
Figurative language -- similes, metaphors, comparisons both direct and implied -- can really trip up writing. It needs to be accurate, yet imaginative. More, it needs to fit the milieu of the story. The famous opening line of William Gibson's Neuromancer is perfect for his world of tech turned to perverted purposes: "The sky was the color of TV tuned to a dead channel."
Other writers have been less skilled. One of the "caveman romances" that were so popular a decade or so ago included this description of a cave woman's mental processes: "The sight derailed her thoughts." Derailed? Instantly I'm out of the Paleolithic and into nineteenth- or twentieth-century locomotives. Talk about being bounced out of the story!
Nor can figurative language be too bizarre. I will never forget a student I had years ago (actually decades ago, which is why I will say this now; the statute of limitations has run out.) He wrote: "In the woods birth and death were inextricably mingled, like vegetables in the great stew pot of time." The first part of the sentence is abstract and pretentious; the second is unintentionally comic.
Finally, figurative language should not be overused. Two similes in the same sentence is overkill. Sometimes, two similes in the same paragraph is too much. Like buildings, figurative language stands out more if it's not too crowded.
All this came to mind as I wrote this morning on my fantasy novel, and almost typed in a really bad simile. No, I won't say what it was. It's gone. Onward.