I keep a basic daily journal.  I usually write down which campground, campsite, and highlights of our stay.  When we stay for more than one night I only make one entry for that specific stay.  While in Florida for 3 months I keep it fairly short and only note interesting things we did during our stay.  When we've done a long trip I will include miles traveled for the trip and occasionally for the day if it was a long haul.  In the past I used to note good campsite numbers for a campground we'd likely return to in the journal, but now I just use the campground map, if there's one handy, and map the sites on it.