Reading produced screenplays is the cheapest film school available, and most writers do it wrong: they read for enjoyment and absorb nothing structural. Read the next one with a pen and page numbers, and it becomes measurement rather than admiration.
Mark five things only: the inciting incident, the commitment at the end of act one, the midpoint, the low point, and the climax. Write the page number beside each. Then do exactly the same to your own script and put the two columns side by side.
What you are looking for is not identical numbers — genres vary, and so do good scripts. You are looking for a large gap: an inciting incident on page 22 when the comparable lands on page 8 tells you your opening is doing something other than starting the story.
Do it with a script in your own genre, and ideally one made for a similar budget. Structure is genre-sensitive: thrillers commit early, character dramas commit late, and comparing across those lines produces confident nonsense.