Understand the structure of Greek tragedies and the historical context of Medea can give you a boost in making sure that your ideas are 100% unique.
Here's a key list of things to look out for to make your interpretation much better:
- Historical context (dichotomies like men/women, god/human, Greek/non-Greek, are pretty cool to at least allude to)
- Wordplay (stichomythia/agon, how is rhetoric used, dramatic irony, etc.)
- Structure of Greek tragedies (maybe understand the plot of some famous ones by other playwrights and how it is different to Medea, and you'll realise that Euripides is very unconventional, ask yourself why? and how would his audience react? This is a good start for unique interpretation albeit its unrelatedness to VCE English)
- Read Aristotle's 'Poetics', or a summary of it on tragedies if you can, and note the similarities and differences between the archetypal and perfect tragedy in Aristotle's perspectives to Medea. Understanding the similarities makes your essay much clearer because there are aspects common in all plays (noble stature of the tragic hero, turn of events, catharsis, how punishment exceeds the crime etc).