Make time for important work, not routine
Blocking out time for projects, aka scheduling a meeting with yourself, is necessary for a lot of people to make progress on their most important projects. I also know that some people routinely observe a "quiet hour" or "planning and solitude" and find it helpful. However, if you have a job that requires serious mental horsepower at times, don't squander your best hours on email and routine paperwork. For most people, routine stuff is best done in between the important stuff. If you know that the most important, most engaging things are under control and on track, you are more likely to easily handle routine matters effectively and efficiently at other times. On the other hand, if you schedule time for routine stuff, especially early in the morning, it is likely to drag you down- your brain knows you have more important things to do.