Poetry analysis may be quite different from poetry comprehension.
Poetry analysis is probably examining the mechanics of the poem(s) you are being asked to analyze. What is the rhythmic meter or pattern, what is the rhyme scheme, what writing devices (alliteration, onomatopoeia, etc.) are used and why? Poetry analysis may also include looking for symbolism in words or phrases of the poem that add additional layers of meaning to the work.
Poetry comprehension is specifically analyzing the meaning of the poem. What is the author trying to convey as a message through the poem? How effectively is that message presented and what was done to make the presentation effective or not clear?
Poetry analysis is showing that you recognize mechanics. Poetry comprehension shows that you understand meaning.
Poetry analysis can be perceived as a difficult task perhaps because poetry often uses figurative language—words that "paints" a mental picture in our mind is "imagery." All examples below are forms of imagery, and all imagery is a form of figurative language—not literal language.
A poem about the joys of spring and the fears of winter may be referring to the joy of youth and the fear of death, where a metaphor is used to compare the stages of life to nature's seasons: the theme is "aging." Note, for instance, Henry King's lines from "A Contemplation upon Flowers:"
Would have it ever Spring:
My fate would know no Winter, never die...
The author is saying that he would wish to always live in the "Spring" of his life and never know "Winter." (*Authors often give hints about important elements in their poems by capitalizing common nouns.)
Another thing that you should prepare for is the use of several kinds of literary devices. There are two lists shown in the source links below: they have devices such as similes, metaphors, personification, imagery and repetition. These are not the only devices, but they are very popular.
In the following, Emily Dickinson personifies a train with human traits like: "lap," "lick," "stop to feed," and "then…step…"
I like to see it lap the miles,
And lick the valleys up,
And stop to feed itself at tanks;
And then, prodigious, step...
The third line of Sonnet 29 (below) personifies heaven as "deaf."
Metaphors and similes are important. Stevie Wonder's lyric, "You are the sunshine of my life" is a metaphor. The woman has the same characteristics of the sun. Patrick Swayze’s “She's Like the Wind” provides a simile: she has the same attributes as the wind, but the comparison uses like or as. Review your literary terms!
Another important piece of information for understanding a poem is to follow the punctuation rather than stopping at the end of a line. A period, semicolon, question mark or exclamation point indicate that a complete thought has been presented. A comma or a dash indicates that more information is to follow that may be necessary to comprehend the author's message. Note the lines from Edgar Allan Poe's "Annabel Lee" where the complete thought ends with the second line:
And the stars never rise but I feel the bright eyes
Of the beautiful Annabel Lee;
Sentence structure and word order offer deeper understanding. Refer to Shakespeare's Sonnet 29:
When, in disgrace with fortune and men's eyes,
I all alone beweep my outcast state
And trouble deaf heaven with my bootless cries…
First of all, if you pull up the entire poem, you will see that the sentence that begins on line one does not end until the eighth line—with a semicolon. This is not a run-on sentence, for you will note the use of commas. It sometimes helps to be able to put the words in another order for easier understanding. Shakespeare is trying to order the words to create a specific rhyming pattern. (E.g., eyes rhymes with cries; state rhymes with fate.) It is true that knowing the definition of words used, as with anything, also helps. The first line means when I am disgraced by luck ("fortune") and men ("men's eyes"); the second line says that I cry because I am an outcast. "Trouble deaf heaven" means he calls to heaven, but it seems deaf. Switch the word order and see if it helps.