Brevity is an absolute necessity of creating a good logline. You should go through many drafts to make sure every adjective is the most perfect and evocative and above all accurate. Get out your thesaurus find the best words for the job. You can’t afford a single extra character.
Choose your focus carefully. You need to pinpoint the most important through-line of your story. What you pick must be dynamic: you need to describe action, conflict, challenge.
The easiest way to phrase your logline is to state the genre, an attribute of the main character, and what the character needs to achieve to meet a challenge. Of course, you may see your script as a slice of life or a series of vignettes or something else that doesn’t lend itself to a clear statement in this form, but attempt it.
“The Last Thing She Did” is a romantic comedy in which a ditsy writer struggles to overcome her reliance on a dead friend’s advice in order to meet a deadline.
Try to avoid generalities. You want to nail what makes your script unique, so don’t waste your time comparing it to previously made films. Save that for your marketing pitch.
Your logline doesn’t need to tell the ending of the story. It just needs to impel a producer or reader to make the effort to open it up. Show you have an interesting and unusual protagonist who must meet an unusual and interesting challenge, and you’re already ahead of the game.
So you say your script doesn’t fit into an easy category of genre or have a single or readily defined hero or heroine. That may be the way you think of your story, but another reader might have a different impression. Try describing the action of your script to a friend and see what shakes loose. It’s fine to know you’re written a masterwork that defies description, but you won’t have much luck getting it made unless you can find SOME way to explain it.
A Word about Plot and Character Vs Theme
The best loglines focus on character with an emphasis on the major conflict or challenge that forms the central arc of the plot. It’s good to include whatever details make your story the most unique: an unusual setting or antagonist for example.
You may be tempted to make your logline about the script’s theme instead but I recommend against this. Producers are interested in the practical matters of who, what, where, when and why. They are less interested in your philosophy on the nature of life or the specific demon that drives your hero’s quest.
In my opinion, the easiest way to write a good logline is in the form of:
[Film Title] is a [genre] IN WHICH a [protagonist] struggles to [challenge to overcome].
Problematic loglines often use passive language and the word about, which can find you expressing your intentions instead of the action. Something you want to avoid at any cost is a logline that focuses on how you intend the viewer to feel instead of what they’re going to see.
For example (don’t do):
“The Last Thing She Did” is a transcendent human comedy about the way we connect through laughter and memories.
Nice, but it doesn’t tell us a single thing about the script. We don’t know who the characters are, what it’s about, where it’s set, and we’re vague on the genre. When you use a logline, remember you are pitching your story to practical people who want to know if they can make your script into a film that they can sell. Save your beautiful writing for your dialogue, and your writer’s commentary