I found this MO question while writing my own teaching statement. I'd like to point out that the [Notices of the AMS published a survey][1] which identified quite a few themes in successful teaching statements. I will paraphrase the list, beginning with the most-cited comments:

 1. *Specific* examples linking philosophy to practice.
 2. Dedication to teaching.
 3. Good writing.
 4. Thoughtful reflection on teaching.
 5. Student-centered.
 6. Match between individual and department.

Here's a [handy rubric][2] from the [University of Michigan][3], also informed by a survey. 

  


  [1]: http://www.ams.org/notices/200710/tx071001308p.pdf
  [2]: http://www.crlt.umich.edu/sites/default/files/resource_files/TeachingPhilosophyRubric.pdf
  [3]: http://www.crlt.umich.edu/tstrategies/tstpts