I divide the landings between myself and the student after each flight. I log mine, and they log theirs. If I help them out by moving the controls at all, it counts as mine. Some days I log no landings at all. I list the exercise number and student's name in the remarks column.
I also log any flight time in tailwheel aircraft and any aerobatic flights. The Insurance company for the Extra 300 I fly seem to want that information every year.