To write an essay on this poem for a graduate course, you should begin by location a good critical edition, including both versions of this unfinished poem. Next, you should familiarize yourself with Keats' sources. The best known account of the titanomachia, or battle between the Olympic gods and the Titans, is Hesiod's Theogony, but Keats may have used intermediary sources as well.
As a graduate student, you are also expected to be familiar with the major critical positions on the nature of Romanticism and the poem itself. Consult the MLA International Bibliography, which should be available among the electronic resources in your university library website, using an advanced search function to access articles published in the past 5 years about the poem.
Rather than focus on all the Romantic elements in the poem, you might consider, for example, how the treatment of the Greek gods, and especially Apollo (use Nietzsche for this) is typical of German and English Romanticism. You might also consider the exotic setting, the emotional tonal, the emphasis on the individual, the glorification of art, or the prosodic structure of the poem.