How do you keep track of your game?

I basically do the same. Started using a notebook in Sims 2 as I rotate and needed to keep track of where I left off. I use a notebook in Sims 4 with a section for each neighborhood, list my sims living there leaving room for adding family members as they come along. Also include info on each such as job, age, date of birth. I use a pencil so can change info as needed. I lost my game due to computer issues so am basically starting over, but haven't had time due to real life being very busy right now. Slowly creating my sims I want in my game and found that the notebook came in handy as can look back and see the names of my sims and their details so can be close to the sims I had before. Can't wait to start really playing again!