First of all you have to read the script entirely without stopping once and without thinking too much. Let it get in!
Then you have to find out who’s story is mainly told, who is the main character (the protagonist). This is not always the person who is all the time present or in the foreground.
After having got a convincing result it could be useful to list the characters which are helping the protagonist, which are on her/his side (e.g. the police in Fritz Lang’s “M” who know that the murderer is a sick man and his “lawyer” at the gangsters’ trial).
It would be helpful to find out who is the antagonist and to list her/his helpers.
Now you need to know what is the protagonist’s goal (her/his want and her/his need); the reason why this story is told.
You read it again and you write a Story-Step-Outline (which means that you transfer the script back to its story; you filter the story out of this film on paper).
You try to find out the basic structure of this “film on paper”: the acts and the sequences. The only chance to find the acts (introduction, confrontation, solution) is if you look at it from your POV on the protagonist’s journey.
You need to know about the bascic structure as this is telling you objectively if the story is really told or not. All classics consists of well told three acts.
In addition you start to list
- all characters with some remarks for each of them,
- all topics (the important ones with the scenes’ numbers where they are mentioned directly or indirectly).
Try to find out which is the main topic and then try to find arguments whether it is treated in an interesting way or not. Try to find out if the treatment of the main topic is too didactic or if there is a chance that the audience will swallow and digest it. Important: Think about if the main topic is universal and if a lot of people could be touched by such topic.
The most important term in script analysis is “Theme”/”Final Impact” but to understand this asks for at least a one month full time workshop.
Now, you have only to think and to work out something like another 100 questions concerning the script, but these you will find out yourself – someday!
If you are an author, you should remember this…
The very important INITIAL IDEA (event, person, novel, etc.) wants to be transferred to your STORY and probabely to (1) a SCRIPT (or a novel or a stage play or poem or …) which will eventually be
(2) SHOT DIGITALLY someday and hopefully very well (3) EDITED and finally presented to the most important in filmmaking: (4) THE AUDIENCE.
Only with step (4) your masterpiece will become real, in fact, you have to seduce the audience to make/complete your film.