In general, the speaker describes a number of things that are typically thought to be beautiful and then explains that his mistress's qualities are not as conventionally beautiful as these objects. He doesn't use any adjectives to describe the sun, but he does report that his mistress's eyes are "nothing like" it, and he also claims that "Coral is far more red" than her lips. He calls snow "white," contrasted with her breasts, which are "dun" (a dull grayish-brown color in comparison). Her hairs are like "black wires," and there are no roses in her cheeks, not like the beautiful damask roses in a garden. Her breath "reeks," and "music hath a far more pleasing sound" than her voice when she speaks. Finally, rather than move like a goddess does, the speaker's mistress simply walks on the ground. The contrast of "white" and "dun" makes the mistress seem ordinary, typical. Her cheeks are not like "roses damasked," a phrase which carries a connotation of wealth and elegance; instead, "no such roses" are visible in her cheeks; again, she is not this idealized figure. She is a normal woman who sometimes has "reek[ing]" breath that doesn't smell of "perfume" and who has a normal speaking voice. He "love[s] to hear her speak," however, even though music is more "pleasing."

In short, the narrator contrasts his mistress with all of these other, more beautiful or appealing items in order to make the point to be found in the final couplet: that he does not need to flatter her, as some sonnet-writers do, with false comparisons because she is "rare" and wonderful in so many other ways.