“What is that script about?”

A logline is a one-sentence plot summary; it is also known as a written pitch. The first step in writing a logline is to ask yourself: “What is my script about?” and then answer the question.

A logline is not a tagline, as seen in a movie trailer or movie advertisement, such as in this example:

BAD LOGLINE EXAMPLE #1

Will Jenny overcome her demons before it’s too late?

WHY IT’S BAD

•           It sounds like a movie trailer.

•           It doesn’t tell us what the story is about or what the major conflict is.

•           The phrase “too late” doesn’t tell us what’s at stake in your story.

•           It includes the character’s name, which loglines should not.

•           Jenny could be a child, a teen or an adult.

•           It doesn’t tell us who Jenny really is.

Loglines must clearly and succinctly convey what the core of your story is about, using your story arc as your guide.

BAD LOGLINE EXAMPLE #2

It’s a story about a teacher who learned life lessons as she discovered the meaning of life.

WHY IT’S BAD

•           It’s written in the past tense.

•           “It’s a story about” is too wordy and unnecessary.

•           We don’t know what type of teacher or person she is.

•           “Learns life lessons” and “discovering the meaning of life” identifies the themes of the story, and it repeats the word ‘life.”  (A logline must not include the theme of your script; it should be evident.)

•           It doesn’t tell us what the story is about or what major obstacle she must overcome.

TOP TEN LOGLINE TIPS

1. Describe your story and setting, your protagonist, and his or her major goal and conflict/obstacle.
2. Use present tense.
3. Every word must do double duty. Less is more.
4. Indicate how your characters are distinct by using strong adjectives to describe them.
5. Show the reader how your story is different and unique, and what sets it apart.

To read more: http://www.screenwritersutopia.com/article/a4d71de0