Make sure you use your sources and articles effectively. Citing and referencing is par for the course, and doing so extensively may get you a 2:1. However, I find that most First Class essays require a clear engagement with the critics and their arguments, deconstructing their points to fit your own etc. As someone mentioned above, raising contrasting points made by other scholars only to effectively disagree with them is another useful technique that achieves the same engagement. After that it's just a question of coherent argument, focus, and style.