Start with writing down the answers to the following questions.
Who is your main character? What's the most important information about them?
What do they want? Why do they want it?
Why can't they get it? What/who stands in their way?
How do they try to get round it?
What's the setting?
What's the story about? What's it really about? (is there an underlying theme/message eg love conquers all, triumph over tragedy, the role of women in today's society)
Now try writing a pitch using your answers and trying to be as specific as possible, and following this formula:
This is a story about X who wants Y but is prevented by Z so tries A, and in the end B happens.
This is a story about Isabel Freeman*, back in the UK after 15 years abroad, who wants something more in her life than being labelled a wife and mother in provincial suburbia, so she starts a job that leads to a passionate affair with her boss which then goes wrong.
That's 50 words. Is it any good? Well, it covers the main points and tells us who, where, when, what and why (the theme - women's loss of identity when they're wives and mothers). It's low concept - there must be thousands of books that this pitch could describe - but it's the pitch for Adultery for Beginners and it worked for me!
*Technically, film elevator pitches don't name names eg housewife instead of Isabel, but they work better for books by naming the characters. I suspect this is because films tend to be more plot driven, books character driven, but don't know for sure.
At last! I've got my finger out and have committed to running some day courses:
Writing a Novel - 31st July in Bath and 18th September in Truro
Getting a Novel Published - 1st August in Bath and 19th September in Truro
Contact me on firstname.lastname@example.org for more info...