Vincent,
Teaching journals are very personal and individual in their format. Early on, I had a large notebook which, along with written notes on the lined pages, was filled with post-it notes on most every page. The post-it notes were on-the-fly thoughts written in real time. I think my original idea was to transfer the thoughts onto the page, but they remained. So, as just for example, the format can be quite varied.
Barry Westling