I'll participate also!
I'm not sure where you are starting, so I'll post here an edited explanation I gave to a non-technical group about preparation for a GTD implementation:
From several Yahoo groups on GTD, I'll give a summarization of what seem to be good first steps which are rarely described.
The basic points are to figure what YOU LIKE so that you will use your system, otherwise it won't work and require a lot of tweaking and changing.
REMEMBER that you are seeking a way which will permit a "brain dump" of tasks in months and years to come (as well as be useful to pull together what you already have on your horizons now).
AND your system should permits some reflection on your short and long-term goals, and picking next actions to move forward on them, so it should be something you would be willing to spent time with and not make you feel frantic or rushed.
So, here is my list for pre-GTD contemplation, all appropriate to sitting with your feet up without lifting a finger except maybe to make some notes:
1. Give a lot of thought to what APPEALS to you to handle and use. What "rocks your boat" that applies to list making?
-fountain pens? Then you would like a paper approach.
-high quality paper? (again, paper approach)
-notebook? (in what form? There are lots of Moleskine notebook fanatics, for example, but others like planners and the ability to customize forms and print them out)
-high tech? Think about a PDA or PDA cell phone, or computer.
-any preferences for leather, metal, plastic? Any color preferences?
-what do you carry around already? Can you use it or adapt it to a GTD assistance device?
2. Give a lot of thought to when, where and how you would ACCESS a list of "to do" items and also recording new items as they occur to you. Any constraints?
-on the fly? multiple locations? (weighs against computer or internet-based lists)
-in the car? (think about something with voice recording capacity)
-any feelings about size of your information capture device? (me, I like slim things and don't want to carry extra weight, so avoid a planner and like 3 by 5 cards in a leather jotter)
-at your desk? (computer would work)
-multiple computers? (that does take research, especially in how to synchronize the information flawlessly)
3. Think about how TECHNOLOGICAL are you and what you might want to do on a computer.
-like to design paper forms? would color printing appeal?
-use internet information repositories? More likely if you want to share your lists. The most favored of these include a site called "Remember the Milk," various internet calendars, and on-line wikis (look into these if you are interested, but they seem to be in relatively early days of their technologies).
-privacy concerns? (might weigh against internet repositories)
-willing to learn new programs? Would have to be willing to find and try out candidates and master whatever looks appropriate and believe the effort would be justifiable (if not, take a look at the features of your wordprocessing program and other programs you know already)
4. Does your EMAIL generate or support a significant portion of your activities or obligations?
-a lot of email input would weigh in favor of using something like Outlook or another program which links emails to tasks
5. Are there any OLD or NEW HABITS or ROUTINES you wish to track or record?
-make a check list? make a chart?
-use to frame steps? micromovements?
-keep a food journal? sleep journal? water journal?
6. Only thereafter make a shopping list and start to pull stuff togther ...
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Hope this information is appropriate to add at this point of the discussion.