I like to break up days and structure them. You have breakfast, work for two hours on a project, check your emails, work on another project for another two hours and then lunch. Your day has to be a measurable process, in order to minimize aimless drifting. Of course, you can have some days on automatic pilot, and there’s nothing wrong with drifting in and of itself. But you can’t do that every day—you’ll never get anywhere.