Simile
It uses like or as to make a comparison.
Vandana and I are best friends.
Vandana and I are like two peas in a pod. (simile)
Metaphor
It compares two things without using like or as.
A strong metaphor will suggest that two different things are similar.
E.g. My desk is a mess.
My desk is pigsty. (metaphor)
Idiom
An idiom is a common expression that can’t be taken literally,
but the meaning is understood.
E.g. All the best.
Break a leg. (idiom)
Hyperbole
It is an exaggeration.
E.g. I am impatient for my birthday.
It feels like my birthday will never get here. (hyperbole)