The Specifications Master Table Of Contents [TOC] is a handy tool for other things than writing the project specifications. I find that it is always informative to review the master list of specifications while thinking about the building that you are designing.
For instance, during the latter part of Schematic Design, if you review the Specifications Master TOC, you will almost certainly see several things that you have not incorporated into your thinking about the building yet. Some, like finishes, are not critical at this stage. But seeing Overhead Doors in the TOC might remind you of waste removal or package deliveries that would require an overhead door. Another example: seeing Decorative Concrete Paving might make you realize that you should consider its use - before Construction Documents are 80% complete.
There are just too many things to consider to be certain that you have a complete concept. Using the Specifications Master TOC as a checklist late in Schematic Design, halfway through Design Development and about 20% into Construction Documents will give you fewer things to rework in the final days of design and they will be better integrated.
You are also starting the spec-writing process by using the Specifications Master TOC in this way. We took our Specifications Master TOC from our spec-writing software, SpecLink+, and first deleted all the spec sections that we never use and added Division 0 documents that we preferred. Next we color-coded the remaining specification titles to indicate if our master of the spec is "ready-to-use as-is" (black), "needs a quick review" (green), "needs editing" (brown), or "never been edited" (red).
The difference between the last two categories is that "needs editing" means to customize the spec for this project, while "never been edited" means you will need to spend extra time making decisions about the products and methods covered in the spec.
A copy of this master table of contents would be renamed with the project name and during each review the section names that we decided not to use were struck-through. Late in Construction Documents these sections would be completely deleted, but not before we were sure that they would not be used. As the specs were actually written, we changed the color to blue, and when ready to print, we changed the color to black. The Specifications Master TOC became a process checklist and ultimately was printed as the Table Of Contents of the Specifications for the project.
Hopefully there is something about our methodology that will help you make your method better. Our Master TOC is downloadable here.