Compare Shakespeare’s sonnets 18 and CXXX
Sonnet 18 is, of course, the famous "Shall I compare thee to a summer's day" poem. This sonnet builds upon a theme of imperishable love (and beauty), especially when it is preserved in a poem written by William Shakespeare.
Much has been written about how, in Sonnet 18, Shakespeare takes an unusual point-of-view in his major comparison - that is, of the beauty to the summer's day. A common image, apparently, that other poet’s made the loved one appear similar to the summer's day, their minds making the quick assumption that summer days were pretty fine things. Shakespeare, in his unique vision, finds the flaws of the summer's day, and bounces them off the beauty he writes about. The loved one's beauty is "more lovely and more temperate," meaning the summer's day cannot compete for loveliness or moderation. Summer days, after all, suffer the polarities of excessive heat ("too hot the eye of heaven shines") and cloudiness ("and often is his gold complexion dimmed"). Those elements that affect the summer's day, changing it to not always ideal conditions, will not have any affect upon the beloved. ("But thy eternal summer shall not fade")
Shakespeare ends the sonnet with a gentle boast of his own powers as a poet: "So long lives this," the "this" being the poem, which will outlast everything, and provide immortality to youth, beauty, and love.
So you want to keep in mind the unique perspective of the poet, and how nature is played against human beauty to appear less fair.