Below is a link to the Birth Plan template from my health care provider. Some of it might be specific to my provider, but I think it covers a lot of bases...
In my childbirth ed class, the instructor said to just start writing down things that were important to you about how the birth goes and then try to narrow it down to 7-8 bullet points.
She also recommended that you call it "Birth Preferences" or "Birth Wishes" and that you begin with a short paragraph about you and your partner (if relevant) and maybe include a picture, so the staff have something other than just your preferences to associate with you. HTH!