When we're young, we're often taught in school to think about what poems mean: their themes, their images, the feelings they evoke. At the higher levels of literary education, however, you may be asked to evaluate how a poem works. One of the keys to analyzing this "how" is understanding a poem's structure. Like little machines, poems are built in different ways to accomplish different goals. It's your job as a literary critic to show the makeup that makes a particular poem run well.
Formal Poetic Structures and Purpose
One of the most important aspects of analyzing poetic structure is to categorize the poem. This usually means becoming familiar with some of the more common poetic forms out there: sonnets, ballads, haiku, odes, sestinas, villanelles, elegies and many others. Part of understanding formal poetic structure requires thinking about the poem's purpose. Is it a love poem? Is it written in memoriam of the dead? Is meant to evoke a simple image? Is it meant to be read publicly?
Stanza and Line Structure
All poems have a stanza and line structure, even if they are not so apparent. If the poem is broken up into discernible stanzas of equal or unequal size, this is important to note. Similarly, consider whether the lines in the poem are of roughly equal length. Once you establish the stanza and line pattern, you can see where the poem deviates from this structure. Focus on these places, because poets often use deviation from a pattern to highlight important words or phrases.
Rhyme Scheme and Meter
When we think of poetry, we usually think of lines with consistent rhythm that rhyme in some predictable pattern. This is not always the case, however. To analyze a poem's structure properly, it is crucial to find out what its pattern of rhyme is. Is it written in quatrains (groups of four lines) that rhyme at the end? Is it written in rhyming couplets? If there is no observable rhyme, it is written in free verse. Similarly, it is important to see discover its rhythm (meter). Count out the number of stressed syllables in each line.
Speaker and Tone
Although we don't always associate tone with structure, the point of view from which a poem is written is part of how it is put together. If there is a persona who is speaking the lines of a poem, this must be noted. Similarly, note whether the poem is written sincerely, or spoken with an ironic tone. Robert Browning's "My Last Duchess," for example, is spoken from the perspective of a duke who has had his wife killed. The poem's tone, therefore, is ironic.