Know that a short movie script is usually less than 20 minutes long--though some go to 30--and may deal with more than one character or story line. However, if you’re making a movie script that is all about a joke, it probably needs to be only 2 to 3 minutes long.
Realize that it’s best to keep your short movie script simple to avoid unnecessary expense, especially if you’re funding it yourself. Elaborate stunts and in-depth character studies are not suitable for a short movie script.
Be aware that as in all movies or literature, you need to have a character, setting and a problem. A short movie script will probably focus on only one event in the life of one character. Make the event, setting and expectations easily established by choosing something familiar such a birthday party, Thanksgiving Day or other common event.
Acknowledge that the character needs to have a problem that’s easily recognizable to the viewer. Since the viewer can’t see inside the character’s head, the character needs to take action that makes the viewer see his problem.
Make sure the audience understands why the character needs to solve his problem, so show what’s at stake.
Know how your short movie script will begin and end before you write it. This will help you understand your message and write your script.
Read other short movie scripts to get ideas and instruction. Short movie scripts can be found online to view for free (see Resources below).