Perspective in a poem is quite literally the view the poet or speaker takes of the poem's subject.  As Nancy Sullivan points out in her article on perspective in poetry:

[the poet's] perspective, the unique tilt of his mind, provides the necessary arrangements that [his or her] technique will turn into poetry. . . . Every poem, like the mind from which it springs, views life from a particular point of view.  [Sullivan, Nancy. "Perspective and the Poetic Process."  Wisconsin Studies in Contemporary Literature 6.1 (Winter-Spring, 1965): 114-131. Print]

Identifying perspective is particularly difficult in poetry because the reader can never be certain whether the poem reflects the perspective of the poet or the speaker within the poem.

 For example, in Billy Collins's poem "Introduction to Poetry," Collins makes it clear that he, as both poet and teacher of poetry, is speaking:

I ask them [that is, his students] to take a poem/ and hold it up to the light/like a color slide . . . I want them to water-ski/across the surface of a poem/waving at the author's name on the shore. . . .

This is Billy Collins the poet speaking.  The last two lines of the poem represent Billy Collins the teacher: "They begin beating it with a hose/to find out what it really means."  In this poem, Collins's perspective (or, more accurately, perspectives) create the tension between enjoying a poem and understanding a poem--from Collins's perspective, very different literary activities.

Understanding perspective in a poem, then, requires the reader to ascertain, to the extent possible, how the poet perceives the subject of the poem, and this requires an understanding of the poem's subject, tone, mood, diction.  In addition, the poem's context is often helpful in understanding perspective--When did the poet write it? Is there any biographical information that might shed light on the poet's purpose in writing it? Is the poet addressing something in the larger society?

Perspective in poetry tends to encompass a bit more than it does in prose. If you are asked, "What is the perspective" of a poem, you should consider, "What is the overall attitude, message, or viewpoint being spoken within?"

One of the most difficult things about analyzing poetry is the fact that it does not always present itself concretely. This does not mean, however, that all poetry is just ambiguous and therefore it is up to the reader to create the perspective. Use evidence from the text itself to determine the perspective. If it helps, use the following as leading questions for your brainstorming:

1. What is going on in the poem? Does this poem tell a story, describe an object or situation, narrate an event, or simply express feelings?
2. Who is the speaker and how does he or she feel about the above?
3. What is the overall message that the audience can take away from this poem?

In many ways, perspective is a broad term that is the summation of several smaller terms. In order to find and define it in terms of an essay question, this pursuit could be the focus for your thesis statement. You could examine and analyze three smaller literary areas to come up with the overall perspective. Though there are several literary aspects to poetry, I'll suggest three of the ones that tend to be easiest and quickest in terms of analysis.

First, determine who is the speaker of the poem. Remember that the "voice" of the poem is not necessarily the author nor a character (especially if the poem is not narrative poetry or a poem that tells a story). Identifying the speaker may be as specific as knowing (from clues in the context of the poem) that he is an adult or a child, a man or a woman, or even something like a soldier, or it may be as broad as simply stating, "The speaker is angry." It obviously depends on the poem. But if you can give a pretty clear idea of who the speaker is, again, using context and examples from the poem, you are well on your way to defining the overall perspective.

Another area to analyze is the language or the diction of the poem. Remember that by definition, poetry does not always follow the same sentence and paragraph structure as prose. This heightens the importance of individual words. Analyzing specific words that hold very strong connotations will add to defining who the speaker is, and also start to point to the perspective of the poem.

Finally, I always find it helpful to identify the scene in a poem. Is it a specific physical place? Or, if not, what clues in the lines help you determine a likely time and place. Like identifying the speaker, sometimes identifying the scene will be as broad as saying, "The poem takes place in a memory," or a "dream," or even simply a place of "fear or despair."