What is a consistent lens to look at an artist's body of work?

Another filmmaker and I are [planning on] watching every single woody allen film in order. To be honest, I know I will gain a lot from it but I am not sure what I want to get out of it specifically. I know I want to take notes but I’m not sure how to go about it because I don’t know what I’m looking for. This will probably become clear as time goes on, but I was wondering if you had any suggestions…