This is a very easy yet very complex task to do but I'll try to help you. We have to remember that this poem doesn't use rhyme, but he does use other sound devices, such as alliteration, assonance, and consonance. We also have to remember what is a simile, iambic patter, repetition and assonance.
Simile: A simile is a figure of speech that makes a comparison, showing similarities between two different things.
Example:
-"Those soldiers are brave as lions"
-"Her cheecks are red as a rose"
Iambic pattern: It's a style of writing. Like using abab or abb,etc. Similar but different. However this poem is a free verse.
Repetition: Repetition is a literary device that repeats the same words or phrases a few times to make an idea clearer.
Example:
Because I do not hope to turn again
Because I do not hope
Because I do not hope to turn…
Assonance: Rhyme in which the same vowel sounds are used with different consonants in the stressed syllables of the rhyming words, as in
penitent and reticence.
Example:Assonance is the repetition of identical or similar vowel sounds in neighboring words (as in "fish and chips" and "bad man").
Now which of these 4 matches a bit with the description above?