Swamped with work and overwhelmed by tasks? A list-making guru promises to help you take control of your life, writes Aengus Collins

It's modern life. We juggle and we prioritise, but we always have more things to do than we quite know what to do with. We all have our tactics and our tools - chief among them the to-do list.

But we're inept with lists, selective when a thorough approach is required. We clear the easy tasks, but let the vague and difficult ones linger until it's time to start a new list (slightly neater this time, perhaps, as if that were the problem first time round).

On their own, our lists are never enough. What we need is structure, self-discipline, a healthy dose of anal retentiveness. A system. Enter David Allen and his book Getting Things Done, or GTD as it's referred to by the hundreds of thousands of people who swear by its life-changing efficacy.

GTD is about more than to-do lists, but not that much more. That's its beauty. It tells us that our instinctive list-making response to overload is the right one - all Allen adds is that we need to complement our usual behaviour with a bit more rigour, a bit more consistency, and a lot more groundwork. A lack of groundwork is where we tend to go wrong with our list-making, he says.

There are five separate stages to Allen's GTD system (see panel). Making to-do lists should only come in at the third stage, but most of us dive in with our lists when we're really still only at the first stage.

"People confuse capturing all the things that need attention with actually getting organised about them," Allen says.

"The capturing or collection phase is only a preliminary - you then need to make discrete decisions about each item. Is it actionable? Is it something I can do in less than two minutes? Is there a specific date on which it needs my attention?"

The two-minute figure is an interesting one. The most clear-cut rule in the whole GTD system is that if there's anything on your to-do lists that can be done in less than two minutes then you should do it straight away, irrespective of how high- or low-priority it is. The rationale is that it will be quicker to do it now than to defer it. Even if you ignore the rest of GTD, Allen tells me, living by the two-minute rule will add six months to your life. He's only half joking.

Allen is 60 years old and has a black belt in karate. He wrote Getting Things Done in 2001, but the ideas crystallised in it had been forming for the previous two decades when he was developing personal productivity programmes for major corporations in the US. His big break came in the early 1980s when a senior executive with aerospace giant Lockheed brought him in to design a programme for 1,000 of the company's executives.

The first of GTD's five stages is the most daunting. A mammoth "stuff-gathering" process, it involves putting all your "incompletes" - your projects, tasks, bills to pay, magazine articles to read, everything - into an in-tray (or as many as it takes). The idea is you'll only stop juggling all your things to do in your brain if you get them out of your head and into your new system.

Success hinges on the comprehensiveness of this initial collection phase. "There's a light-year difference between getting 95 per cent of your 'stuff' out of your head and getting 100 per cent out," says Allen.

It's only by getting everything into the in-tray to be assessed and organised that the brain can start to relax. "Your head gets to let go," he says. "The alternative to using a system like GTD to manage your workflow is to use your psyche to do it. But your psyche has no sense of time, so it reminds you all the time about the things you need to do."

We tend to think the problem with being overloaded is that we can't remember all the things we have to do. But the reverse is just as big a problem, according to Allen. We can never forget all the things we have to do. That's why we wake up in the middle of the night thinking about the light bulb we need to buy.

I suggest to Allen that for most of us the prospect of reducing our entire universe of commitments and projects to a neat pile of paper in a set of in-trays might seem a near-impossible challenge. He says he has done everything to make his system as easy to use as possible, but that we can't expect miracles. The only way to get on top of the things you need to do is to know what those things are. And he stresses how quickly most people get going. "In general, it takes a couple of hours to understand the basic ideas behind GTD, a couple of days to capture all your 'stuff' and get it structured, and a couple of weeks to hit cruise control. After a couple of months, it's automatic. Until you've actually done it, it's hard to describe how big a difference it makes to your experience of work and life. Until you get to that point, all I can say is 'trust me, it does'."

GTD has been aimed primarily at business people so far, but putting order on our lives isn't just a corporate or professional requirement, it's a basic human need, and Allen feels that, five years after his book's publication, GTD might have reached a tipping-point of sorts. It's spreading beyond the business world and starting to reach a broader audience as word of mouth spreads.

"The system is most immediately attractive to the people in the most pain," he says. "So I work with a lot of mid- to senior-level executives, people who are maybe moving levels within an organisation and finding that their existing systems are being overwhelmed by their new workload.

"But I also work with soccer moms and dads. And I've got a big following among the clergy - they're on top of the God stuff, they say, but they could do with some help with the day-to-day church stuff. So it's not just for business people. They just had the most pressing need for it. Once you have things that you need to complete, projects you need to track, then you're right in it - you're in GTD. You need to define the project, define the outcome you're after, and define the next actions you need to take. That applies in the same way whether you're a parent, a student or a CEO."

Allen followed 2001's Getting Things Done with Ready for Anything in 2004. It wasn't a revision or an expansion of the first book or of the GTD system. He says there's no need.

"The core of the system is bullet-proof at this stage," he says, surprisingly definitively. "I'm not going to write another edition because I haven't had any feedback saying that it's needed. The challenge for me these days is to find ways of communicating GTD more effectively. I've got better over the years at describing it, at conveying the simplicity of the system. It's a matter now of seeing how widely it spreads."

• www.davidco.com