Usually the story really begins at the moment when the first character faces the difficulty that he or she has to solve, and it better be a clear difficulty, and he better realize that he must do something. Dramatic form means action, and action brings tension. So the awareness of the tension, and the clarification of what the nature of your tension is, helps to build the whole script.
ACT ONE: ESSENTIAL ELEMENTS
TONE: Very quickly you want to establish the tone of the script: is it a serious film, a comedy, a fantasy, a spoof? Let people know right away that it is okay to laugh, to cry, to dream, etc.
THEME: You will also want to establish the theme of the film - what message are you trying to convey: “Don’t judge a book by it’s cover”, “The underdog triumphs”, “Good versus evil”.
WORLD OF THE STORY: As the story begins, you will introduce the world of the story - where does it take place? What is different and interesting to this world? What are the rules of this place?
CHARACTER INTRODUCTIONS: At the same time, you will introduce the principle characters to the audience. Be specific and original. Let us know their age, how they dress, walk, talk. Give them a scene in which they stand out from the others. Let the audience know these people are special.
INCITING INCIDENT: The inciting incident (or point of attack) is the moment when the dramatic conflict announces itself. It’s the first perception of the predicament to come, and usually, a moment that is very visual.
MAIN TENSION: And this predicament sets up the main tension around which the story will be built: Will they fall in love? Will they rob the bank? Will they escape alive? Will they do all three?
THE STAKES: The stakes have to be clear in order to show the audience how and why this tension is important to them, or - more importantly - what will happen if the character does not solve his/her problem. It should be huge - a matter of life and death.
OBJECTIVE: A character’s objective or goal is what drives him. This should be very specific, very clear. How badly does he/she want something and what are the lengths he/she is willing to go to get it.
LOCK-IN: The first act concludes once the main character is locked into the predicament, propelling him/her forward on a new quest trying to accomplish a specific goal. Now the reader/audience knows the character, the predicament, and the objective, so everything else is about the future.