A metaphor compares two dissimilar things that share the same characteristics, without using "like or as." The following example is a metaphor in the Prologue of The Canterbury Tales.
Describing the Monk, Chaucer writes:
And that a monk uncloistered is a mere / Fish out of water, flapping on the pier (lines 177-178).
Chaucer is speaking to the fact that a monk, a man of God, who is not cloistered/shut away in a monastery, is out of his spiritual element.
An example of hyperbole (exaggeration) can be found with the Friar:
He knew the tarverns well in every town
And every innkeeper and barmaid too
Better than lepers, beggars and that crew,
For in so eminent a man as he
It was not fitting with the dignity
Of his position, dealing with a scum
Of wretched lepers; nothing good can come
Of dealings with slum-and gutter-dwellers,
But only with the rich and victual-sellers. (238-246)
This description talks about another holy man, the Friar. Chaucer had little time for religious hypocrites, and he describes several in the Prologue. The Friar is one. When Chaucer speaks about the elevated social position of the Friar, he is being sarcastic. He exaggerates when he talks about his status, that the Friar could not possibly be expected to mingle with the poor or diseased; no, he was much more "at home" with the bar staff, the rich, or people selling food (victuals)...(hardly what a man of God should be doing).
Finally, imagery in Chaucer's work abounds. (Imagery, of course, uses descriptions to paint a picture in the reader's mind). I have included two. The following describes the Knight.
He wore a fustian* tunic stained and dark
With smudges where his armor had left mark (71-72)
*fustian - coarse cloth
This description praises the Knight. He is a humble man, but his worth is seen when he removes his armor, for the intensity of his fighting has worn stains and smudges onto his tunic. He has honorably fought, and immediately on arriving home, he goes on a pilgrimage to thank God.
Or, Chaucer's description of the Pardoner is classic:
This Pardoner had hair as yellow as wax,
Hanging down smoothly like a hank of flax.
In driblets fell his locks behind his head
Down to his shoulders which they overspread;
Thinly they fell, like rat-tails, one by one. (662-666)
Another man of God who didn't do his job, this description shows how Chaucer felt about him.
Hope this helps.
I will give you one of each to get you started.
A metaphor implies a comparison between two seemingly unalike things. An example would be when the summoner's face is described as being like it is one fire, or when the Miller's mouth is described as being "a furnace door."
Imagery uses language to evoke any of the five senses. An example would be the visual details in the description of the Wife of Bath. The crazy number of kerchiefs, the red hose with garters, her bold red face and her gap teeth all serve to draw the picture of a lady who is full of life and who does her own thing.
A hyperbole is an overstatement. An ironic overstatement would be the suggestion that the Friar is "a noble pillar of his Order." It would be more true to say that he is one of the most corrupt people on the journey.