GTD

The most important foundation is found in David Allen's book, Getting Things Done. I strongly recommend you read the book, particularly before trying to adopt any of the "tools" I may present later. The tools, while interesting, are even more powerful when arranged into the framework that Allen suggests.

As a quick summary of GTD, it's all about getting things out of your head. More precisely, it's about getting everything out of your head, and into a trusted system. Another important discovery relates to propelling progress through a series of "next actions". Simply put, we do away with "to do" lists, and replace them with "next action" lists. Actions are organized into "contexts" - places you'll be in, or resources you'll need to enable the next action to be performed.

That trusted system is flexible, by the way. It can be paper-based (the so-called "Hipster", or Moleskine school), or it can be electronic. I've tried both over the years, and have settled on the electronic method. Either will work, and it's purely a matter of preference, although I've found it incredibly difficult to mix models.

For some more immediate reading, in advance of the book, here are two excellent outlines of the principles of the system:

1. A quick summary of GTD
2. A concise outline of the elements of GTD
   

For motivation behind why all this is relevant, read an excellent article by Scott Berkun entitled "Attention and Sex".