Hope I can help.
The writer's notebook is a composition type notebook. While it can be set up several ways, I have used it with two sections. The front of the notebook is for collecting ideas. Often this personal narratives, and the children write in these almost everyday at home and school. In the back, this section is used for follow-up to mini-lessons. Making a list of first times I did something and last times, revision strategies, and forth.
Then when the children are ready to take a seed idea, they move their idea out of the notebook and work on drafting the pieces. Often these pieces are saved in a folder. One side labeled still working on this and the other side finished for now. At the end of the unit, I collect everything, and place that in a hanging folder for the kids to look through for best words at the end of the year to send to the next grade.
One little tweek I'm going to try this year in a binder. Last year I had handouts that were lost in the shuffled. I'm going to try and have a writing binder. I'll hole bunch the folder to fit in the binder, but I'll have a place for the handouts as well. I'll use dividers for collection ideas, organization, elaboration, revision, and grammar. We'll see if it works. It's amazing how we are always trying to find a way to do it better.