When I sit down to plan for the year, I try and gather all the infromation I can. I look at standadized tests, ask collegues, consult the book, and use prior experience to prepare my yearly schedule. Once I establish my yearly schedule I being breaking the lessons. I am typically a one lesson - one day schedule, but have found through experience that some lesson just can not be taught in one day. These days I doucument, and will make alternative problems for the students to discuss.
My planning is not very detailed, with the student participation leading discussions. I have a couple key points that I want students to explore through out the lesson, but how we get there can be very different between each classes.
When I started planning for AP Calculus this year I did not take the same approach. I did not have any previous experience to help guide me through, and I recieved no assistance with material, I was a man on an island and had to make sure that my kids could swim. I used the book heavily to plan these lessons, I still used students questions to guide the lesson but made sure to hit on specific concepts that the book considered important.
Next year I will play on my experience of both seeing the AP test along with where my students this year struggled. I feel that planning always needs to be revisitited and revised