Louis is writing a speculative script for a movie. which elements should he keep in mind while writing?

Iwould say that to write this kind of script, louis needs to decide the type of writing you would like to do (comedy, drama, etc), you might need to consider the type of audience you would like to have. write a sample, a draft where you include all the options you have in mind, you can use referential  movies like your favorite ones.  study the format of the movie, in order to understand what it is going to be about, find a perspective.  when you have a general idea, try to find somebody who can read it, get feedback, that would you improve and modify ideas. finally, write the complete version, and rewrite if it is necessary, you need to be confident about your work,