I hope that I will not be judged as a heretic, but the only thing that I never liked about the GTD system is the use of 43 folders.
I find that there's too much paper shuffling involved with the 43 folders system. For anyone interested, this is what I do:
Prerequisites: a) Microsoft Excel or another spreadsheet program.
b) Knowledge of (i) the Autofilter feature for sorting your lists and (ii) the Custom Views feature, in order to make the Autofiltering function truly automated.
c) Generally, some proficiency with Excel is useful.
I use a spreadsheet to enter all my Next Actions. One Next Action is entered per row. The spreadsheet has the following columns:
A. A straight serial number for each row.
B. Date of entry of the Next Action.
C. The Project number related to the Next Action (that is, each Project is identified with a serial number) and this number appears in every Next Action for the Project.
D. The Project description (or title).
E. The Next Action. This is entered in this column either in the case where the Next Action is related to a Project or is a "standalone" (single) Next Action.
F. A column headed "Context". One may enter the usual contexts (@Phone, @Home, @Work, @Anywhere, etc.etc.)
G. A column Headed "Waiting For". Here I enter the person's name or initials from whom I expect the Next Action.
H. A column to enter Calendar dates for Next Actions with a fixed date.
I. A column to mark the date done of the particular Next Action.
Given the above data, I can easily create Custom Views to show me pending Next Actions by context, Wating For Next Actions, Calendar dates etc. etc.
Now, on to the 43 folders substitution:
I store temporarily all my Next Action documents in three physical piles (categories) sorted by number as follows:
1. A category for Projects listed by Project number - see column C above. I have about 30 Projects outstanding.
2. A category for Next Actions that are not connected with any Project. Here, the serial numbering of column A above is used. Currently I have about 20 non-Project related Next Actions (concerning work).
My Next Actions and Project-related Next Actions are not bulky and I therefore keep them in plastic folders. I use post-it notes to write the appropriate serial number on each plastic folder.
3. I also keep a third pile of documents (category) for my Someday/Maybe type of documents.
On top of each pile (category) of documents I keep a single sheet of paper containing an index of Projects and an index of Next Actions. These indices are printed directly from my spreadsheet. Thus, if I want to retrieve any document, I only need to perform "Find" in my spreadsheet to see the relative Project number or Next Action serial entry. Alternatively, I can look it up in the above mentioned printed indices.
With this method there is no need to physically move any document forward each day. Sorting the spreadsheet by the Calendar column enables me to see what, say, today's Next Actions are, if they concern a Project or not, and where the supporting documentation may be found in one of the two piles of plastic folders.
I hope that I described the concept sufficiently clearly. If not, please ask me and I'll try and explain it better.