Use evidence from the text, use transitional words, write what you think about the writing, writing a conclusion is about your final thought, and what you think about the topic.
You can write a strong conclusion by recapping everything you discussed and if there was a rebuttle point, again prove why the argument was not strong enough.
Explanation: In a sonnet, a two line stanza is typically referred to couplet...and it's usually structurally at the ending of the poem...in the case of a fourteen line poem (sonnet).