When I was doing office work, I usually finished my work early. I worked quite fast and I delegated some tasks to my subordinate. We usually talk about what we need to do for the week and we plan as to who will do what. For each day, we set a deadline before the actual deadline, and that strategy hasn't fail me. In my 8 hours a day in the office, I would usually finish my tasks for the day before those 8 hours.