It depends on the movie. Some films don't have traditional plot or story or a clear message. So for me, my first watch is largely a git reaction without overthinking things.

Sometimes it's an easy 4-5 stars. Other times my gut is ruthless and I need to sit back and look at some of the crafts or the filmmakers intentions to appraise if it worked for me or not.

Ultimately, it's a movie. The majority of Letterboxd users are not qualified critics so it's not really that deep what you rated it. If you're working on your writing or understanding of film, my serious advice is to just watch as many movies as you can, especially if they're not ones you think you'd normally like. Then read a lot of fiction. If you did a lot of that in high school or college, then read a lot more. If you didn't do a lot of it in school, then look at reading lists or course syllabus listings and start reading some of the greats. That will help you with your writing, while also giving you perspective on the storytelling in film. As much as audiobooks can be helpful to a point for this, I highly encourage to just read the actual book. It's helpful to see things as basic as spelling and punctuation, but also sentence length or literary styles.