Getting back to reading scripts and why, well, obvious, you want to learn. Want to be a better writer, so one easy way to do so is to READ. In the last post, I mentioned a few places where free scripts are. But when you read them, don't just "read" them. Break them down.
First, always read shooting scripts. Don't read the scripts published in book form, these are not shooting scripts. Get the real scripts, on normal size paper if you print them out, which will have the "real" amount of pages. Here, with the shooting script, you want to find out what happens when, where, and how.
For example, on what page does the inciting incident start? You know, the inciting incident is when the story starts. Like in Apocalypse Now, the story starts when he gets his orders to find Kurtz. This is something you want to know. Your story can not start too late. Find out how character is developed, and when, and for how long.
When is the first obstacle? The second, third and so on. How does Act I end? On what page does Plot Point One happen? And Act II, when and how does this end?
These are the things you want to study when reading a script. Because when you write yours, you will copy this structure. You will have your inciting incident happen around the same time, as well as the plot point and the rest.
Here is a pic of MARATHON MAN - one of my favorite scripts. It's all banged up because I've read it so many times over the years. Have studied it. Broke it down. I know what works and when. Do the same.