One of the doctoral students in my program sent this link around: http://www.insidehighered.com/advice/instant_mentor/weir18. It's about how to read and sort through student evaluations. I thought this was really helpful advice on how to approach student evaluations of your teaching.
I found my student evaluations from this past semester very interesting. My advisor and I went over them together and that was extremely helpful because she helped me shift through them and determine which comments I should give more thought to and which comments I should just let go.
After I read this article, I rememberred that a friend of mine said her statistics professor gave an online survey after every class, asking students to rate the class on a few questions. I wrote this professor and asked him about this. He said that he did it for the first 8 classes because, at that point, things seemed to be going fine. He said that almost all the students answered the surveys at first.
He asked about pacing, how well they understood the lecture, and what questions they had remaining. These seemed like good questions and I'm considering doing the same this coming semester.