As I mentioned, coming in early and leaving late is deplorable, not laudable. One of the reasons this happens is simply that you don’t take the time to determine what’s worth doing–in advance. Consequently, you try to do as much as is possible in the hope that it’s enough.
One way to get around this, each day make a list of a few things you want to get done. Not more than 3 or 4 things that would each take an hour to accomplish. If something else arises during the course of the day, it can go on tomorrow’s list, or later in the week. Then, at the start of each day, look at that list and ask yourself, when I accomplish everything on this list, will I feel satisfied for today? Can I walk away feeling good about what I’ve done?
You’ll quickly find the things that aren’t worth doing. And you’ll quickly replace them with things that will give you a sense of accomplishment. Enough that you won’t fall into the work as many hours as possible in the hope that it’s enough mentality.