I have a rough sketch of what I want to teach for the week mapped out in my head. Typically, I end up teaching a little more than what I had anticipated. The only time I write out detailed plans is when I have a sub. My bf calls it a "script" because it ends up being 6-8 pages of plans. I try to make the plans "foolproof" and I want the kids' day (the sub's day, too) to be seamless.