In the last few months, I have been working hard on adopting a more efficient mode of working. Perhaps I shouldn't state this here, where any hiring committee can see it, but the transition to working independently was a rough one for me. I'm going ahead and saying it because this is true for most graduate students, although for many of them the transition doesn't really come until they take a faculty job* - and also because I am overcoming it. So after flailing around for a while, I think I've found a system that works for me.
The biggest adjustment initially was adopting something of an 8-5 work model. There are important exceptions I won't bore you with here, but in general, I'm on campus five days a week, and when I am there, I am working on school-related stuff. When I am home, I am not working on school-related stuff (the biggest exception being reading for class, which is allowed at home). I had always liked the flexibility of the academic life, but I had been carrying it too far. So: Structure is good.
I've also been reading a lot of Robert Boice and other writers on scholarly productivity. I'm not as resistant to his ideas as he says some flailing scholars are, not because I am some open-minded paragon**, but because (as one of his students said), "What I'm doing now clearly isn't working, so what is there to lose?" The biggest thing I've picked up from him is the idea of moderation. Don't wait for inspiration on a project, and don't binge on it. I tend not to work for more than an hour at a time on any particular task, with the obvious exception of meetings that last longer than that.
A final thing I've figured out is that I do better with different tasks at different times of the day. Writing is easy before lunch; in the evening, it's nearly impossible. I can read at any time of the day except after lunch, when even a bodice-ripper could cause drowsiness. The early afternoon is a good time for administrivia, mindless tasks, sending email, etc. So I structure my day around my body's clock.
The result is that I've been getting more done and feeling a lot less guilt.
*I work for two deans who don't have big grant-driven projects. As my adviser has gotten deeper into the world of administration, he's given me less and less oversight. And I think it's an interesting way to do things - better to struggle now than in year one of the tenure track.
** Although I am that, too, of course.