Simple:
* The elf was small and pointy-eared.
* She believed in elves and fairies.
Descriptive:
* The mischievous elf played tricks on the unsuspecting villagers.
* The forest was filled with the laughter of elves dancing under the moonlight.
Figurative:
* He was such a skilled carpenter, he worked like an elf.
* Her energy was boundless; she seemed like a tireless elf.
In a story:
* The elf brandished his bow and arrow, ready to defend his forest home.
* The queen of the elves held court in her glittering palace.
The best way to use the word "elf" depends on the context and what you want to convey.