There are a number of beautiful similes and metaphors in "Rime of the Ancient Mariner," and Coleridge also uses the devices of symbolism and personification.
Here is a list of some similes (line number follows each):
"red as a rose is she" (34)
"as who pursued with yell and blow/ Still treads the shadow of his foe" (46-47)
"as green as emerald" (54)
"like noises in a swound" (62)
"as if it had been a Christian soul" (65)
"like God's own head" (97)
"as idle as a painted ship/ upon a painted ocean" 117-118)
"like a witch's oils" (129)
"like restless gossameres" (184)
"as through a grate" (186)
"as white as leprosy" (192)
"fear at my heart, as at a cup, / my life-blood seemed to sip" (204)
"like the whizz of my cross-bow" (223)
"as is the ribbed sea-sand" (227)
"as dry as dust" (247)
"like April hoar-frost spread" (268)
"like lifeless tools" (339)
"like a pawing horse let go" (389)
"clear as glass" (472)
"like music on my heart" (499)
"like one that hath been seven days drowned / My body lay afloat" (552)
"like night" (586)
"like one that hath been stunned" (622)
Finally, this entire stanza is a simile:
"Like one, that on a lonesome road/ Doth walk in fear and dread, / And having once turned round walks on, / And turns no more his head; / Because he knows, a frightful fiend / Doth close behind him tread." (446)
Metaphors are not as frequent, but here is one powerful example: "An orphan's curse would drag to hell / A spirit from on high; / But oh! more horrible than that / Is the curse in a dead man's eye!" (257) This compares an orphan's curse to the curse of a man who has died with his eyes open and cursing someone.
Here is a metaphor/simile comparing the sails of the Mariner's ship when he returns to harbor to fallen leaves: "I never saw aught like to them, / Unless perchance it were / Brown skeletons of leaves that lag / My forest-brook along." (533)
A couple of the above similes are also personification. The sun peering through a dungeon grate and fear sipping the life-bud from his heart give human characteristics to the sun and to fear.
Besides the powerful symbol of the albatross representing guilt, there are at least two other important symbols. The "slimy things" referred to in a couple different places represent the Mariner's lack of appreciation of nature--the very sin that made him shoot the albatross. The "water-snakes," on the other hand, show the beauty of nature. When the Mariner loves and blesses the water-snakes, he loses his guilt (the albatross falls into the sea) and he is able to pray again. The water-snakes represent the redemption found in loving "all things both great and small."
Coleridge use a plethora of poetic and literary devices in his poem, adding to the beauty and depth of its language and sentiment.
Coleridge uses all four of these literary devices in his long poem, Rime of the Ancient Mariner.
Her skin was white as leprosy, the nightmare Life-in-Death was she.
In this line the poet is comparing the appearance of the supernatural female character known as Life-in-Death to a debilitating disease, leprosy. This emphasizes the idea of death and the feeling of impending doom for the mariner.
Near the end, the mariner has been saved, but the pilot’s boy initially believes he is dead. When the mariner suddenly begins to row the boat, the boy says:
Ha, ha . . . full plain I see, the Devil knows how to row.
This is a metaphor because the poet, using the boy, is comparing the mariner to the devil. Of course, this is completely dependent on the boy’s perception. We realize that the mariner is just a man.
And hark the little vesper bell,
Which biddeth me to prayer!
The poet is personifying the bell, portraying it as something that willfully calls people to come and pray. In reality it is just a ringing sound that people know as a signal.
The albatross itself is the most famous and well-known symbol from this poem. The mariner pointlessly murdered the beneficent albatross early in the story. Later, the crew members hang the dead bird about his neck as a symbol of his guilt. People often make references to this in real life when they are suffering from guilt or a burden of some kind, saying something like “This is my albatross.”
Coleridge uses all of the above repeatedly in the poem. One example is the personification of the sun's behavior as the sailors all become incapacitated with thirst:
"As if through a dungeon-grate he peered
With broad and burning face."
The sun appears to stare at them as though to taunt them as though it is aware of their situation.
There are numerous Christian symbols in the poem, as the sailor deals with sin and then redemption through suffering and pain.
Coleridge also uses metaphor throughout the poem, one memorable one is when he uses the supposed look in an eye to stand in for a curse:
Each turned his face with a ghastly pang,
And cursed me with his eye. (lines 215-216)
There are also a number of similes including the following:
[E]very soul, it passed me by,
Like the whizz of my crossbow! (lines 223-224)