People read and comprehend roughly one word per second. Therefore, each visual segment’s minimal length should last as long as it takes to read the text associated with that image. Sentences should be pared down to be as condensed as possible.
It was the summer of 1977 when the town caught the fever of quick love, and Julia Raynes’ adolescence burst into the fires of passion for Harold Stark, the mayor’s only son, in spite of the fact that her mother worked for his father.
Could be pared down to:
Summer 1977. Julia’s passion ignites for Harold.
Using the back cover text of your book is usually the best place to start to find inspiration for your trailer script. If starting fresh (or not), here are the concepts you will want to cover in your trailer (adapted from http://www.screenplayers.net/loglines.html):
- Reveal the main character’s SITUATION
- Reveal the important COMPLICATIONS
- Describe the ACTION the main character takes
- Describe the main character’s CRISIS decision
- Hint at the CLIMAX—the danger, the “showdown”
- Hint at the main character’s potential TRANSFORMATION
- Identify SIZZLE: sex, greed, humor, danger, thrills, satisfaction
- Identify GENRE
- Keep it to the proper length
- Use present tense