The "Snowflake Method" is a novel-writing tool created by novelist/theoretical physicist Randy Ingermanson. While many novel-writing methods encourage a linear outline or skeleton for your novel, in the Snowflake Method you begin with a short summation of your novel and expand it into a full text.
First Sentence and Paragraph
The first step of the Snowflake Method is simple: Write a single sentence that summarizes your book. This is a hook for your novel -- how you would describe it given 10 or 15 seconds. The rest of your novel will move outward from this sentence. Now, take this sentence and convert it into a full paragraph that outlines the novel's plot. Ingermanson recommends a five-sentence paragraph: one sentence each for the story's beginning and end, and three sentences describing the major turning points.
Defining Your Characters/Expanding Your Plot
For each major character in your novel, write a single sentence each outlining that character's narrative, motivations, goals and conflicts, and what he learns over the course of the story. In addition, for each character, write a paragraph that describes his individual story. After you have these outlines for your major characters, rewrite and expand the summary of the novel that you previously wrote. Expand each sentence of the first five-sentence paragraph into a full paragraph -- this should take up roughly a full page.
Larger Character Work and Synopsis
You now build on and expand the previous character work you've done. Write a full, page-long description for each major character, and half-page descriptions for other important characters. In these descriptions, retell the novel's plot in the individual point-of-view of each character. Once you are satisfied, expand and rewrite the overall plot of your story as informed by your character work. Take the one-page summary of the novel and expand it into a four-page synopsis. Because you've begun to describe how the characters and plot interrelate, you should have a better idea of how to make the larger complexities of the plot work.
Character and Scene Details
Take your previous character information, and get down to the nitty gritty of character details. Nail down attributes such as eye color, birth date, hometown and height. Provide expanded descriptions of your characters' goals, motivations and conflicts. By now, you should have a solid foundation of character and plot to begin sketching how your novel will be constructed. Create a list of all the scenes you will need to write to fulfill every character's arc. Ingermanson recommends making this list in spreadsheet form for easy editing.
Scene Synopsis and Draft
Sketch out two or three paragraphs describing each scene from your list, noting any imagery or dialogue you want to include. Ingermanson says that this step is optional, but a good warm-up for the final process of drafting. You now have the tools to write the first full draft of your novel. You already have all the important plot and character structure sketched out; now you're ready to connect the dots without worrying about resolving larger plot elements while you're writing.