Learning to document well. I've written runbooks for tasks that would involve me reading through the code for a day and brought the time involved down to 5 minu

Learning to document well. I've written runbooks for tasks that would involve me reading through the code for a day and brought the time involved down to 5 minutes (and that can be handed to junior engineers or new hires). I've also seen really great documentation written by a senior engineer that cut days off of tasks, long after that engineer had left.