I'm not a huge advocate the various formalized personal organization methodologies, like Getting Things Done (GTD), or the Forty-Three Folders (one for every day of the month, and one for every month of the year). I approach organization like I do software development processes: just enough to get the job done, and no more. Also like software development processes, I don't believe a single organization methodology works for all people and all situations.
Mrs. Overclock (a.k.a. Dr. Overclock, Medicine Woman) introduced me to what OfficeMax calls Durable Poly Color File Folders. These are flexible plastic file folders that come in four colors: red, yellow, green, and blue. I use these to organize paperwork in my briefcase for either day-to-day work, or for travel. My system is based on just the file folder colors, no explicit labels. This appeals to the most primitive parts of my brain, requiring virtually no higher level cognitive functions. For me, this is a good thing.
Red: the red file folder contains stuff that I absolute have to get done today. If I have a form I have to give the HR person at work, it goes in here. If I have bills to mail and I'm not stopping by the mailbox immediately, they go in here. If I have notes for a meeting I'm going to, they go in here. If I have a CD-ROM or even a USB drive of a presentation I'm about to give, it goes in here. I look in the red folder during the day to see what's left undone. If I get home at night and there's still something in the red folder, I know I've screwed up somehow, and it stays in the red folder. Red means Important!
Yellow: the yellow file folder contains stuff that I may need in an emergency. When I was pretty much doing nothing but field technical support and handling customer escalations, the yellow folder contained lists of super secret field service passwords, work, home and mobile phone numbers of every subject matter expert and manager in existence from which I might need help, any scrap of paper or digital media that I might need while working a customer problem. Since I'm not doing that anymore, the yellow folder still contains mostly things like company directories of my clients, contact information, and the like. Yeah, a lot of that stuff is on both my laptop and my PDA too, but I've learned not to trust anything that needs power for real emergencies. Yellow means Caution!
Green: when I travel, the green file folder contains all my travel documents: flight schedules, rental car agreements, reservation confirmation numbers, street maps, anything I might need enroute to get me where I'm going. At home, it contains forms I find useful: blank timecards, certification from the State of Colorado regarding the status of the Digital Aggregates Corporation (frequently needed by the contract administrators or HR people at my clients), a few copies of my resume, and still some Denver or Boulder street maps. Green means Go!
Blue: the blue file folder contains stuff I've printed off the web, white papers, journal articles, anything that I want to read and might have time offline in a spare moment to do so. Most of the stuff that is in this folder gets tossed after I read it unless it seems important enough to file away. A lot of this stuff I can read online, but I find I have a lot of slack time offline while waiting for one thing or another, or just prefer to read at the local coffee shop without having to tote a laptop around or pay for wireless access. The stuff in this folder has a high rate of turnover, as you might expect. If I want to travel light and expect I'll have some reading time, I'll just grab the blue folder out of the briefcase and take just it with me, secure in the knowledge that it'll have something in it worth reading. Blue means Cool!
Why plastic? They're much more durable than the cardboard folders which also come in colors but which damage easily in my rough-and-tumble experience. The plastic folders, for me, have been indestructible, and protect their contents against the occasional coffee spill, beer mug condensation, or lead spray from tactical shooting. It's a simple system that's worked for me.