A short film essay becomes easier to write when it begins with a question that can be explored in a few scenes. A narrow focus gives the piece direction and helps the reader understand what your examples are meant to show.
Write the question first, then choose two moments that complicate it. For each one, separate a brief description from your interpretation. This prevents the essay from becoming a long plot summary and makes the reasoning easier to follow.
Look for a detail that resists your initial idea. Perhaps the same visual arrangement creates a different feeling elsewhere, or a conversation changes your reading of an earlier moment. Including that complication makes the argument more honest and more engaging.
Close with what the comparison has clarified and what remains uncertain. An essay does not need to claim a final meaning for the entire film. A carefully supported observation can offer a satisfying contribution to a much larger conversation.