What do you do when you don’t know what to do? Ask for an example. If you are nearing a deadline and you simply don’t know what the professor wants, email him or her and ask if he or she would be willing to post an example of an excellent student paper on your class page.
Periodically when one student really “gets it” and others do not, I ask the superb paper-writer if he or she would be willing to post his or her paper. In fact, I just did that today with one of my classes. The students are writing their second of four in a series of assignments and a couple of the students are trying but are not quite where I want them to be. I have tried to explain what I mean but then I realized that one of their classmates was doing the same assignment but approaching it differently. The highly-successful students are usually willing to give their classmates a hand, so everyone wins with this deal.
So, what do you do with the example? First, look at formatting. How was the paper set up? What appears first, second, and third in the document that the teacher liked? How many sources are there? Don’t try to re-invent the wheel here. The instructor has told you that this is a really good paper, so follow that paper’s lead.
Make sure that your grammar is good, that you don’t have any typos, and that you have subject/verb agreement. Do you have an introduction, body with transitions, and conclusion? Have you matched the successful paper, without copying it? It looks like you are on track for a much better grade.