What is a common atmosphere conveyed between these two poems?

To His Coy Mistress- Andrew Marvell and The Sun Rising- John Donne. My assignment is to discuss in a 3-5 page length essay on how atmosphere is conveyed in both poems and consider the overall effects of the poems. I'm having the hardest time starting my intro paragraph. i have no idea what to say! All i know is, I'm discussing their diction, detail, syntax, organization, etc. So thats pretty much the only thing i dont need help with. But i don't know how to start! omg im so scared! lol