You already know that in the opening 10% of your screenplay you should introduce your protagonist and show us the things that we will need to know about her personality and environment. One of the protagonist characteristics that you should show is how unhappy or unsatisfied she is, so that the audience will root for her to change over the course of the story. The best way to demonstrate her unhappiness is to put her in a situation that she is unable to handle effectively because of that pesky internal flaw of hers. When she fails at an attempt to deal with some small challenge that most people would find pretty easy, the audience will know that she has problems and will want her to overcome them.
It’s then a good idea to show how much your protagonist has grown by the end of the story by writing a bookend scene at the end of the script that demonstrates that she has overcome her internal flaw (if, indeed, she has). A great way to do this is to repeat that scene from the beginning of the script where she handled a situation poorly, but now that she has overcome her internal flaw, she handles it with aplomb. (Have you noticed that people don’t use the word “aplomb” enough? Or maybe I use it too much. Never mind, we’ll talk about that later.) Regardless of whether or not your protagonist has overcome her internal flaw, you can’t go wrong by including a scene at or near the end of the script to demonstrate the final state of her character arc. Audiences love it when you wrap things up in a nice little bow for them like this, so it will only make your script more attractive if you give that to them.