I don’t care what it is: you need one place and solely one place to write down what you have to do. It doesn’t matter if that’s pen and paper, it doesn’t matter if it’s a full-on OmniFocus To Do app that’s synced across every computer, tablet and phone you own.

Well, there are limits.

If you’re driving behind a very dirty van, scrawling To Do: Clean Me isn’t ideal.

If you’re currently using Post-It notes or you’re strangely drawn to them, stop now. Post-It notes are not your friend. They’re certainly not mine as I’m papyrophobic – I’m a writer afraid of paper – but they’re also definitely not yours because they are like a party you’re not invited to.

The clue is in the name: Post-It Notes. Plural. Nobody ever had one Post-It note with their To Do list on, they have had many, many such notes since the dawn of time or when such notes were invented, whichever came later.

And you need one.

Just one.

It might have to be pretty big: a paper spiral-bound notebook rather than a single sheet. I do definitely recommend computers for about a hundred thousand reasons.

But what’s mandatory is that you have one place.

One place that you write down everything you’ve got to do: it must be one place, without exception, and it must be everything, without fail. You need one system: when you have a task to do, you write it in this one place, then you do the task, then you mark in this one place that you’ve done it.

I say this to you and I start twitching about roughly a hundred thousand things that tell me I’m right to rely on OmniFocus. But if you’re just starting out getting your head clear and if you’ve fallen off this productivity wagon, I know that the first thing to do is to have one place, one system.

How do you know when you’re finished if you have more than one place to check?