I was wondering if there’s any advice that you might have for an essay like this... the title I think I’m going to write on is ‘Is love a narrative force to be reckoned with in epic? Discuss with examples from Greek and/or Lati

what really impresses the examiner is getting your inspiration from material you have come across before (e.g from a set text or reading you've done) and developing an idea you found interesting from there and exploring and challenging it through more research and reading around and exploring what these ideas might actually mean in a wider context (i.e for society or as general ideas which circulated at the time). Starting points for your question are obviously Iliad, Aeneid and Odyssey - there's some important foundational ideas in there, from there I would maybe look at some secondary resources - books written by scholars who have studied love and you might get some ideas about other poems to compare/contrast ideas which have emerged or have been developed/modified from the three main epics. Argonautica is good (a really short greek epic) or have a look at Sappho too for a female perspective which could be a really interesting comparison to the male authors. If you'd prefer to write about Latin poets or in addition to Greek ones as a comparison to Greek ideas maybe try Catullus, Ovid or Tibullus?

Generally though I would say definitely narrow your focus, it's really easy to try and write about everything but if you confine yourself to a format i.e comparing greek perspectives to latin perspectives using a few sources or simply choose one or the other - you'll find it a lot less daunting and the essay will be a lot more focussed.