If you are a student in the audiovisual field, you have certainly heard the tip: analyze the old works. It seems like sloppy advice and they usually don't give it much thought, however, it's the best study tool there is.
It should be emphasized that this does not mean that just watching several movies or series and calling yourself a screenwriter is enough, there is a correct way to dismember a work and its nuances, including a structural technical part that various courses teach.
The technique consists of breaking down the production you are watching into parts and understanding everything that was put there. First, understand the reason that makes that movie or series good (or not, analyzing errors is of paramount importance too) and what calls attention to quality.
Then start analyzing each part. Rewrite the profile of the protagonist and other characters, mention their internal and external goals, their mistakes and qualities, etc. Do the same with the plot, how is the plot presented? What are her important points?
And if you feel safe, analyze the structure. Understand the melodica, the beats, each turning point and how everything that was presented interconnects with the other scenes, what is the function of each object and point mentioned. For this, it is important to know about the script structure and its variables. the books of Syd Field, O Script Manual, The Hero's Journey in Joseph Campbell, Save The Cat in Blake Snyder and The Hero with a Thousand Faces in Joseph Campbell explain well the proposed structures. If you want to know more deeply about structures and analyses, there are modules from Kinematic Idea Factory that explain in practice how to perform this important exercise.
Always use this tool to learn and even to write a new project. Watch that work you didn't like and try to improve it, as you would if you were responsible for that script? This practice will always improve your writing and sharpen your skills.