Compare the themes used in each poem. If it is up to you to choose which poems you will be working on, try to pick poems of a fairly similar theme, otherwise it's hard to get the compare and contrast dynamic. Look at what the two poems are talking about, if they have a positive or negative attitude toward it and for what reasons. Do the writers focus on the same aspects of the theme? Suggest why you think this is.
Relate your analysis of theme to the word or phrase used as the root (the word running down the side) of the acrostic. What does the writer's choice of a root word tell you about their attitude toward the theme? Does the choice of the root word fit with the tone of the poem? If not, ask yourself why you think that is.
Look now at the language the writers use. Consider the imagery they use. Does this reinforce the ideas you had about themes? It's often useful to think in terms of other choices the writer could have made. For example, if the writer uses an animal metaphor to describe the weather and they use a wild horse, what are they trying to say about the atmosphere of the time and place in general as opposed to if they had used an angry hippopotamus instead.
Consider their choice of words, look at particular words that seem important and consider synonyms that could have been used instead and how this would have made the poem different. What does this tell you about the narrator (if there is one) or the different voices in the poems? Do they seem intelligent or not? What does their choice of words say about their emotional states?
Compare how the word used in the root of the poem compares with the general choice of words in the poem. If the poem is full of emotional terms and the root word is something like "Dramatizer," does this affect how you read the poem?
Look at the rhythm and structure of the poem. Ask how the structure interacts with the themes in the poem. If, for example, the poem is all in one long block without paragraph breaks and it is dealing with themes of claustrophobia, then the poet is probably doing this on purpose. Consider again how the root word relates to the structure and rhyme, does it rhyme with any words in the text and if it does why might this be?
Conclude by asking which poem you think was most successful at conveying the message or feeling you think it was trying to get across. Don't offer unqualified opinions ("I think Shakespeare is not very good"), but try to say where and why the poem falls down, or what one of the poems manages to do that the other doesn't.