A good analysis of film media using codes and conventions includes four parts, contention, observation, connotation, and connection to audience.
The contention of the analysis is your headline for what the media producer succeeded (or not) in their media product using media codes.
Analysis of a media product will include some kind of observation, or description of the code. The observation could be seen as the denotation section of the analysis
The connotation is the meaning that is attached to the denotation that you have observed. Here you are answering why the decision was made to use the media code in the way described.
It's a good idea to connect any analysis to the code's effect on the audience. This frames the use of the code to the broader ideas in the media product.
When discussing the effect on the audience, often you are discussing the use of form, story or genre conventions. When media products use of subvert these conventions, this adds to their understanding or creates a relationship with their audience.
'Arrival' (2017) Denis Villeneuve
In ‘Arrival’ (2017) Villeneuve uses camerawork to give the alien a foreboding presence. When showing the aliens in contrast with Louise Banks, Villeneue uses a long, low camera angle shot in order to have a full body shot of both characters. The use of this shot highlights just how much larger the alien is compared to Banks as the use of the low angle has the figure towering over her. This adds distrust of the aliens, and has the audience see Banks as vulnerable. This tension adds to the thriller aspect of the film.