This summer I'm trying something new: a to-do list with a single item. The principle is very simple. You have a "list" with one thing to do. When you've done it, you strike that item through and add a second item. All efforts go toward completing that item. Don't even think about the third thing, even if you know in the back of your mind what it is. For example, the first thing is to grade the student papers and turn in the grades. I've done that, so I kept it on my list but struck it through, writing down the date when the task was completed. Next is finishing a first draft of an article on "receptivity." I have begun that, without writing down item # 3. I know what it is but I won't write it down or think about it too much even. (A manuscript came for review; since that was a quick item I just did it quickly, adding it to my to-do list after it was already complete.) The to-do list with completed items listed can also do double duty as a professional log. You'll know what you've completed in a given month or year.
The main point is to focus on one thing at a time instead of scattering one's attention and getting a fraction of many different tasks done without completing anything. This is especially important in times of stress. I recently had a fire in my apartment in Kansas, where I wasn't living at the time. I have to take care of some of this crap this summer as I work on my academic work.
Obviously, this method doesn't work for non-academic chores. I'm talking about medium to large writing projects that you will complete: a tenure letter, a book review, a chapter... It probably won't work for a graduate student juggling three final projects, who needs to be working on all at once.
In global terms, you should have one item on the list: finish the book, finish the dissertation. Don't be working on two or three book projects, just on one at a time.
This is hard for me because I like flitting back and forth between three or four things at once and also anticipating future projects. I know to some extent what the book after next will be but am actively avoiding thinking too much about it, since thinking about a book you are going to write entails actually writing it.