Take one of your three short papers, on the formal patterns and other objective features of the poem your chose, and shape it into a more formal, 1500 word essay.
A good literature essay asks, and attempts to answer, some interesting questions about the text, and does so using ample textual evidence. Textual evidence is the term of art for the kinds of observations we've been making over the last several weeks about our poems: what the poem says and doesn't say, its patterns of sound, rhythm, and syntax (along with the way these may or may not synchronize with each other), lineation, word choice and lexical levels, verb forms, things that are made present vs. things whose ideas are invoked by figurative language, and so on. Now you get to think about what it all means, what it adds up to, for what kinds of conclusions can it serve as evidence, how it might be useful in talking about a "big picture" view of the poem. From the other direction, you could think of your job as framing an interesting question about the poem for which the evidence you have helps to provide an answer. I think of this process as making a mosaic—finding a way to place the different pieces I have such that the outline of something can emerge.
Now that I've said "outline," a few words about structure. I would highly recommend two practices: outline your draft as you go, and be willing to reconsider, if necessary, the sequence in which you make your points. The first will help in doing the second, and is also good practice for disciplines in which "reading an article" really means, scanning the section headings.
As you work, continue to pay close attention to what the poem says, both directly and by inference. Please stay away from generalizations ("throughout history, human beings have…," "Shakespeare is one of the greatest writers in English"), from information I can find for myself on Wikipedia, and from subjective observations that can't be solidly linked to evidence in the poem. Consider, if only provisionally, the hypothesis that poets say exactly what they mean to say, rather than trying to say something obscurely in verse that might be said more clearly and effectively in prose. (Prose may shape our reading habits, and create certain kinds of expectations that might lead us to feel that way). It's always worth trying to paraphrase especially difficult or mystifying sections, as a discovery exercise.
In going from "report" to "essay," you should cut back on the first person and on narrative about your own process (of course, you can walk the reader through a process of coming to understand the poem but you should know where it's heading). So for instance, a report might very legitimately have content like this: "I don't see a rhyme scheme… Actually, now I can see the poem does have one." In the essay, you'd want to do something like this: "the poem's regular rhyme is subtle enough that we may not hear it at first." Also be prepared to prune evidence observed in version one that ends up not being critical to the analysis (e.g., "like other sonnets, this one is written in iambic pentameter.")
A quick word on introductions and conclusions: the job of the conclusion is to step back, review the questions, the evidence, and the argument, and say, "what do I now know? How confident am I? And what do I not know?" The introduction should be the last thing you write. It should be written from the perspective of already knowing everything the essay will say, which is simply not possible until you have said it. It can do some basic orientation about what the poem is and is about, very briefly; and it should set up for the reader the kind of direction you're going to take in the essay. Without giving away your most interesting conclusions, make the reader curious about what they will be.