Synopsis

One of the advices on how to write a novel in 30 days is to start by writing the synopsis... Now... a lot of people hate writing synopsis. I think it is because people don't know what it is.

Here's a example
Here's a couple more - real life synopsis that are good enough for the editor to buy the book

- What is your book about?
- It is about this man and this woman, who meet and fell in love with each other and get each other in the end of the book.
- Well... yes, every romance novel is about that. Give me a little more details.
- The heroine is N.N, and she is a singer. She wears always this specific jewel and a collector sees it and gets it. The hero is M.M. and he's a private detective, whom the heroine employs to get her jewel back. They have some adventures which lead them to fall in love with each other and in the end they marry. Happy End!
Now, my synopsis is a little longer, but I don't want to talk too much of it, because the more I talk about it, the less I write.

Basically, the synopsis is your story. Now, a synopsis is 1-8 pages, and your book is 200-400 pages (or more...), so you understand that by writing down the synopsis you are not writing the book, but you give a very good idea to the editor what your book is about, and you have a handy outline which you can use to help you write the book. You don't need to start writing from the first line of the first page of the first chapter and then write until you get to The End - you can write a dialogue from chapter 8 first, then a scene from chapter 3, then chapter 13, then the end of the story, and so on. If you have your synopsis, it's easier to keep everything in order.

The Snowflake Method of Writing