SIMILE: compares two things that are not alike using "like" or "as".
The baby is as cute as a button. He is as hungry as a bear.
Metaphor: compares two things that are not alike by saying something is something else.
The boy is a pig at dinner. Life is a rollercoaster.
Personification: gives human characteristics to things that are not human.
The tree limb was waving in the wind. The sun was playing hide and seek in the clouds.
Onomatopoeia: a word that sounds like its name.
BOOM! POW! HONK! HISS! SQUEAK! SPLAT!
IDIOM: a commonly used expression whose meaning does not relate to the literal meaning of its words.
"Under the weather" "spill the beans" "once in a blue moon"