A simile is a description, when an object is said to be like another. The words like and as are found with a simile. For example:
Her hair was like mouldy hay..
He was as silly as a headless chook.
His face felt like sandpaper.
She was as nervous as a cat on a hot tin roof
Metaphors are words or expressions where one object is said to be something quite different. For example:
The road was a ribbon of moonlight
Now, we know that a road can't be a ribbon but it makes a pretty piece of imagery.
A metaphor is makes a comparison without using "as" or "like".
Her gaze was icy.
We distinguish between literal meanings and metaphorical meanings.
The footpath was icy. (literal meaning)
Her gaze was icy. (metaphorical meaning)
He couldn't digest anything the nurse gave him to eat. (literal meaning)
He couldn't digest anything the nurse told him. (metaphorical meaning)
We use metaphors all the time in everyday language. Often we are probably not conscious that they are metaphors.
Your letter was buried under my papers.
That salesman was a shark.
Personification. This is when a thing that is lifeless is compared with something that has human qualities.
The moon danced on the hills in
her bright silver shoes.
Death be not proud, though some have called thee
Mighty and dreadful, for, thou art not so,
For, those whom thou think'st, thou dost overthrow,
Die not, poor death [...]
John Donne: Holy Sonnets, X
Metonymy is where the literal term for one thing is applied to another with which it has become closely associated. Therefore, the crown can stand for a king and the turf for horse - racing.
Milton can signify the writings of Milton..."I have read all of Milton".