Both the Watchlist and Toolkit are continually growing because I almost never do anything exactly the same way twice. After each project, I go through a debriefing exercise, asking myself what I did differently this time around and what I learned. I think about any new templates, spreadsheets, or processes I developed, or substantial alterations I made to existing ones. I reconstruct any I found useful and add them to my Toolkit, often making additional refinements in the process. For the Watchlist, I review the learnings I noted and synthesize the new notes with the existing ones. I ask what worked best on this project and what didn't work at all. What new things did I try, and how successful were they? What mistakes did I make? How could I avoid them in future? When I'm done, I cut a new CD and back it up.
These aren't the only tools that go with me. Because I work on customers' premises and it can be time-consuming to get basic office supplies, I bring my own pens, whiteboard markers, multi-colored highlighters, sticky notes, scissors, glue stick, and stapler. I often take useful and interesting books to keep on my desk and share with my team and others, and I always have a digital camera to capture whiteboard sessions or oddities like cash register screens.
The really essential elements of the Test Manager's Vade Mecum are my notebook, Toolkit, and Watchlist. These give me a head start on every project.