When it comes to poetry, nothing is done randomly. The poet has written his/her poem and used language, punctuation, and structure specifically to create an overall effect. The poet uses the figures of speech to achieve his/her desired effect. If you still struggle with poetic devices; it can basically be divided into four types: form or structure, imagery, aspects that enhances the story or meaning, and those that are used as sound devices. Lets revise how the poet does it.
Refer to your text book and English Handbook for more detailed explanations and examples of figures of speech.

Form Is the poem restricted by a form or free verse? sonnet, acrostic, couplets, limericks, diamante, free verse, etc.	Imagery What pictures is the poet painting in your mind? metaphor, simile, personification, hyperbole
Story What is the meaning or story being expressed? tone, mood, atmosphere	Music  What do you hear when you read it aloud? alliteration, assonance, repetition, pauses, rhyme, rhythm, etc.

Did you know Figurative language is often associated with literature--and with poetry in particular. But the fact is, whether we're conscious of it or not, we use figures of speech every day in our own writing and conversations.

For example, common expressions such as "falling in love," "racking our brains," "hitting a sales target," and "climbing the ladder of success" are all metaphors--the most pervasive figure of all. Likewise, we rely on similes when making explicit comparisons ("light as a feather") and hyperbole to emphasize a point ("I'm starving!")
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