You start with less and tease out room for more interest. This is by far the biggest mistake any writer or filmmaker can make.
But you carry their memory forever. Focus on revealing the essential elements of your story. Finish your description with the title and the log line. But don't panic!
The writers' goal is usually to secure a development deal, and to get paid for turning a story into a complete screenplay. But as you will learn, the better your preparation, the less courage you'll be required to muster.
The typical movie trailer is around two minutes and thirty seconds long. Most actors will get in with money. For these, I focus on the main character, who they are, the world they inhabit, the actual inciting incident that makes the story go.
Michael Hauge has presented his seminars and lectures to more than 30, writers and filmmakers. Now you have to prepare.