I agree with the previous answer completely. Just in case you wanted some specific essays, I thought I would give you some food for thought.
General literary criticism on "The Necklace" often focuses on whether the beauty of the story lies in the surprise ending or in the vision of modern relationships. Possibly the most famous one (that eNotes happen to contain an excerpt from) is called "The Technical Struggle: On Subject" by O'Faolain about the relationships of the Necklace. In opposition is "The Necklace" in Maupassant: A Lion in the Path by Steegmuller, who vows that the characters and relationships in the story are vague at best. According to Steegmuller, the surprise ending is the crown jewel of the story.
In my opinion, however, the more interesting topic revolves around time and "The Necklace." Heck, Madame Loisel ages from a young girl to an old woman in this story! That's got to be hard on an author of a short story! Because of this, I would choose ‘‘The Necklace,’’ in Understanding Fiction by Brooks. The discussion here is about how Maupassant treats long duration of time differently than short duration of time. Fascinating!
Hopefully this gives you some specifics to concentrate on. Now you can do some further research in the "essays and criticism" area of the eNotes website and do some further reading on the subject, forming your own opinion along the way.
There is information right here on eNotes that can help you with a topic for your essay regarding this short story by Guy De Maupassant.
Since you are a college student, might I assume that you have read some of the short stories of American writer O. Henry? If so, you could write a really interesting essay comparing the elements of irony in The Necklace and O. Henry's story The Gift of the Magi. The surprise or "twist" endings in each story reflect on the human condition. In the O. Henry story, however, the characters act out of love, whereas in the De Maupassant story, the main character acts out of envy. You could write an interesting compare/contrast essay on these two stories.
See the links below for more ideas.