Before I write about what I do, I want two offer two general thoughts on the subject at hand:
1. There is a plethora of "goal setting techniques" out there. We all have read at least half a dozen of them; or so it seems. In the introduction of Leo Babauta's Zen To Done, he states he did so and his book is basically a compilation of what has proven most useful to him. Some of those things strike our fancy more than others. I like Seth Godin's Pick Four for instance.
Now, all these things come up with very short time horizons. In GTD however, the horizon for a 10,000 ft level Project is set at "aproximately a year". In other words, the shortest and easiest way to integrate those goal thingies in GTD is to just make it a Project.
Engage in the Natural Planning model to clarify as to why you want to have such a set of short-term goals in your life and so on.
2. This brings me to my second point. Why set goals at all? Notice, most of this goal thingies come with explanations as to why setting goals is important and whatnot. If you want to set goals, make sure you know why.
Many authors seem to think that making more money is a good thing no questions asked and that you should absolutely try to make more money, again, no questions asked. What kind of a worldview is that? Is that even compatible with YOUR worldview?
I believe the "secret" to make these goal thingies work for you, is to first clarify, yes, at the dreaded 50,000 ft level - all questions asked, what the heck your philosophy on goals is in the first place. Which place goals obtain in your worldview and subsequently in your life - possibly as one of many answers to your worldview. So, clarify first what you expect to gain from setting goals.
Now, as to my own practice, I use short-term goals mainly to motivate me to do less. Yes, less is more. Alas, less is less since "less is more" still implies that more is somehow better than less.
To give you a concrete example, I have a 20,000 ft area "historic studies" which is loosely tied to a 50,000 ft item "mental" (freaking bonus, I bring Covey into the picture: he would called this "sharpen the saw" on the "mental dimension of the human experience"; isn't this stuff just a-a-mazing?) and what I do there besides reading an awful lot is to discuss matters with other historians. To bring some pace into the game I have the weekly goal of writing (or responding) two letters to my colleagues. Nothing more, nothing less. Less is important, otherwise my obsession with history would drive me into some form of burn out. But that might just be me...
How you organize this is of course just a matter of taste. You could have two ongoing Projects, with a weekly milestone. You could organize by topic and activate to topics from SdMb during the Weekly Review. There are many possibilities, all of them okay. Don't forget the Tickler.
For me, this creates two Projects per week, each with a weekly deadline. In my Tickler file I have a weekly reminder to start the next two Projects. I like to do this at the beginning of the week. You could also have this as the last action item of the former set of Projects.
It's really just a matter of how you slice 'n dice it.
I do not maintain a hierarichal goal thingie of five years goals down to daily objectives or some such.
