You don't have to teach at KIPP, to experience a high turnover classroom. I started teaching in Sacramento at a Community Day School (a place for students who were expelled or otherwise redirected from regular public schools) and were there for only a 1 semester or 2 semester (one year) stint. My first regular ed class I only had 1/3 (11) students at the end of the year who had been in my class on the first day (lots of switching of classrooms, lots of families moving).

When I'm planning for the beginning of the year, I'm always trying to anticipate how to integrate in new students, and make them aware of my rules and procedures so they make sense and don't seem arbitrary.

Because I'm a geek, I use PowerPoints at the beginning of the school year to teach my rules and procedures. It comes from an idea I had heard of that's non-technological, so you don't have to use wikis, blogs, flickr, TeacherTube, or PowerPoint (although they are all possibilities too). You could just use a notebook that is a guide to your class. Here is what I used, feel free to rip anything off: