With A, I was given a little booklet type thing at one of my appointments that had info about a birthplan, and then a basis for writing one. So it had various headings and questions that we could answer and write info underneath about the ideas we had and what options we would/wouldn't consider.
To be honest, although it was very useful for me to feel "in control" of what would happen, I forgot all about it once I was in labour! lol. I think my labour was exactly as I had said I wanted it to be, but that may have been more down to luck than anything.
There must be some sample birthplans floating around on t'internet that might help?