In writing Sonnet 130, Shakespeare relied very heavily on strong sensory images to get his satirical message across. Imagery is a poetic device that employs the five senses to create an image in the mind of the reader. In this sonnet, Shakespeare draws on sight, sound and smell when he compares his mistress' eyes to the sun, her lips to red coral, her breasts to white snow, her hair to black wires, her cheeks to red and white roses, her breath to perfume and her voice to music.
Sonnet 130, as its name implies, is a sonnet. Sonnets are structured poems that dictate the length, style and even content of the poem. Like Sonnet 130, most sonnets are 14 lines in length and written in a meter called iambic pentameter with an alternating ABAB rhyme scheme. In order to form iambic pentameter, the writer chooses words that alternate between an unstressed and a stressed syllable; the first sentence of the sonnet, written out to show the stressed syllables in capital letters, would read, "my MIStress' EYES are NOthing LIKE the SUN." Finally, sonnets often have a surprising twist to them towards the end; in this poem, the twist comes when the reader sees that, despite his criticisms, the author does actually love his mistress.
Hyperbole is a form of speech that exaggerates the facts in order to make a point. To the same extent that many romantic poets exaggerate the beauty of their mistresses, insisting that their eyes are more beautiful than the sun, their hair fairer than hold or their cheeks redder than roses, Shakespeare decides to exaggerate how unattractive his mistress is. Sonnet 130 suggests that his mistress' hair is made of black wire, her breath reeks, her breasts are grayish brown and her voice is grating.
Shakespeare's Sonnet 130 also uses satire as a literary device. In writing this poem, he was gently poking fun at the conventional romantic poems that were being written by other poets. In pointing out that his mistress' eyes are not more beautiful than the sun, that her hair is not made of gold threads, that her cheeks are not as red as roses and that her breath is not finer than perfume, he was able to make the argument that he loves her just the same for who she is and not for an unrealistic idealized notion of beauty.