The Simile

The simile is a figure of speech in which you compare two different things with each other using the words "as" or "like".

Examples:  Her eyes sparkled like diamonds.
                 She is as quiet as a mouse.

Similes occur everywhere.
We use it to describe someone's manners, their looks, and even their mood. We use it when someone is annoying us, when we're in love, when we need to blow of steam or just to tell someone how we feel.

Similes brighten and spice up our language. They're our own bit of je ne se qua. When you use similes the listener does not have any other choice but to immediatly see and understand exactly what the speaker is trying to convey.

Similes are also used to put more emphasis on the thing that is being described. 
In the sentence "His eyes were as hard as steel", the listener/reader's attention is immediatly drawn to the "eyes" of the person the observer is referring to.

Other examples include,

She worked like a dog on her assignment.

He groand like a bear.

These types of similes are universally popular and are most commonly used.

Apart from these there are other similes that are made up of adverbs or words such as "than" and "as if".

Examples include:

They ran as if for their lives.

He is larger than life.

My milkshake's better than yours. (as the artist Kelis proclaims)