The synopsis is to the writer, what a flea is to a dog – irritating and inconvenient.
Writing a synopsis spoils the joyful moment of writing ‘the end’, which is why I suggest writing it before you begin your novel. I have found it reassuring, to know the beginning, middle and end. Helpful, to be acquainted, with the who’s, why’s and how’s. Exhilarating to deal with plot holes before they evolve into black holes. And this pre first draft synopsis, isn’t set in stone. Creativity is supported, rather than stunted.
Regardless of when you write your synopsis, ask yourself these questions and answer them in the third person, present tense.
Q. Who is the main character and how does the action start? Describe the inciting incident (beginning).
Q. What is your character called to do? What (or who) tries to stop them? What happens to put them in danger or induce conflict that affects the character (middle).
Q. How is the conflict resolved? What has the character learned or how have they changed? (end).
Once you’re certain your synopsis includes major elements of your story and you have illustrated how/why your protagonist evolves, it’s time to edit. Give your synopsis attention, hook the publisher/agent, demonstrate you know your book and don’t forget to include the ending!
Stick to the essential elements of your story – avoid sub plots.
Stick to pivotal characters, those who influence the plot – avoid minor characters, regardless of how funny/interesting they are.
Stick to concise language – avoid suspenseful build-up that sounds like a book blurb.