Back when I was still a wee scriptwrangler, I bristled at loglines. What's the point of trying to sell your script to someone too lazy to read it? I knew that my work was special and brilliant, and the only way they'd see that was to read the script itself. Then they'd see brilliance and complexity and all that jazz. But a logline -- it's like trying to capture an ocean in a teacup. Yup, I was full of it.
I paid for this, of course. Truth is I couldn't really explain most of my stuff even to my friends. It meant a lot to me. Some readers could pick out stuff they liked. But mostly they asked difficult questions I didn't have answers for. That's the thing about loglines. Sooner or later you're going to have to come up with one, even if it's just to stop your aunt from stumbling onto your story problems over Thanksgiving turkey.
Loglines are simple to create but endlessly difficult to perfect. To reiterate, a reader wants to see:
The main character.
The supporting character and opponent, where applicable.
The main on-screen action.
The hook. The hook is basically the main selling point of your script -- what makes it unique.
Try it. Combining all these elements almost always leads to a skewed version of your story. I have a friend writing a story on the background of a wedding, and the wedding keeps pushing itself forward, for example. Or you can't balance the love story against the mob story. Or, well, it sounds like something we've already seen.
There are two valuable lessons here. First, the elements of a script rarely line up the way you expect. LISTEN to that. Say you're writing a script set in your hometown. But in the logline, suddenly it looks like it's ABOUT your hometown. Listen to that, because that may be how your audience will see it.
The second lesson is that the only way to make it compelling and clear is to think VISUALLY. What does the audience see on screen? Let's go back to "Walk the Line", the Johnny Cash script. It would be simple to say, "life of Johnny Cash." But the story starts when he isn't watching his older brother, who dies in a horrific saw accident. That guilt follows him through the rest of his life, and brings focus to a story or drug and alcohol problems, endless road shows, etc. The writer found the one moment that could drive all that.
In the wake of his brother's accidental death, a young man's struggle to find warmth and love drives him to become the greatest outlaw singer of all time -- Johnny Cash.
Now we know HOW the writer is attacking the story. (And we know what the writer is selling.)
Another writer might take a very different strategy on the same material. Usually, that strategy plays out in the opening actions. A story about what a great American Johnny Cash is might start with his time in the army, or a more idyllic vision of his rural childhood. An expose would start with him cheating on his wife AND his girlfriend, and destroying his own reputation on stage.
Think concrete. Think in terms of combining. And let that one event that typifies your script take shape on the page. Define your strategy in a single line. And then? Then you take that idea, and put it in your script, where it was meant to be all along.