Convey both your story's concept and theme, and tell the full arc of the story .
Here is a template LOGLINE you can use - just fill in the blanks:
(TITLE) is a (GENRE) about a (DESCRIPTION OF HERO), who after (INCITING EVENT), wants to (OUTER GOAL) by (PLAN OF ACTION). This becomes increasingly difficult because (OBSTACLES AND COMPLICATIONS)
(TITLE) is a (GENRE) about a (DESCRIPTION OF HERO) who must (OUTER GOAL) or else (DIRE THINGS WILL HAPPEN)
To pitch your screenplay effectively, you need to have a compelling and clear LOGLINE and SYNOPSIS. In order to write one, you must have a clear understanding of your script.
When writing your logline, try to answer these questions:
1) What is my concept? My main conflict and story?
2) What is my theme? What am I trying to say with this script?
3) What is the genre?
4) What is the beginning, middle and end?
Overall, the LOGLINE needs to convey the full arc of your story. Three sentences, max.
Make sure you check out our NOTES ON PITCHING YOUR STORY to the industry too!
A slightly longer telling of your story. You add more plot detail and character development than the logline. Using words to suggest tone, it introduces the main characters, the conflict and the overall arc of the story. You should always write it in the structure of your script, so it will reveal the pacing of the film. Visual images are necessary. Go here to read notes on writing proper loglines and synopses for professionals to read
When writing your SYNOPSIS, try to answer these questions:
1) Who is your main character?
2) The audience will relate to your main character because...?
3) Your main character's objective is...?
4) Who is your antagonist?
5) Your antagonist's objective is...?
6) What is the main conflict of the script?
7) The catalyst is...?
8) The climax is...?
9) What is your beginning, middle and end?
Overall, when writing your SYNOPSIS, use visual images to convey the story as much as possible. If the reader can see the story in their head, then they will want to watch the film.