Here is a nice little article on Getting Things Done (GTD) and Goal-Setting from David Allen. Definitely worth a read. Here’s a short excerpt:
THE VALUE OF GOALS
What we focus on changes what we notice. Our brain filters information, seeing one thing in a situation instead of something else, based on what we identify with, what we have our attention on, what we’re looking for—more or less consciously.
The reason for long-term goals is the permission they give us to identify with the greatest value we can so it changes our filtered perceptions. The future never shows up (have you noticed?—it’s always today!). But playing with it as a working blueprint can be a remarkably useful tool to see things (and how to do and have them) that you never saw before.