By Leo Babauta

One of the revelations of GTD is the very simple (and in retrospect, very obvious) mandate to write everything down. Capture all your thoughts on paper (or digitally) -- don’t let them float around in your head, where they will surface at inappropriate times, stress you out and be forgotten when they are needed. Have an idea? Write it down, right now, before you forget. Thought of an errand you need to do? Capture that as well. Just remembered something for your grocery list? You know what to do.

If you’re not already capturing all your thoughts or tasks immediately on paper, or in a digital system, and carrying that around with you wherever you go, I highly recommend you start today. Even if you don’t implement the entire GTD system, this one step can make a big difference. It eliminates a lot of the stress from this stuff floating around in your head, and keeps you from forgetting a WHOLE lot. Trust me.

Here are a few tips on ubiquitous capture, whether you already have a system or not:

• Some of the more popular methods: A little notebook, a Hipster PDA, a PDA or smart phone, or a Moleskine notebook. Each of these methods has some very passionate proponents, and each has its advantages and disadvantages. I prefer a simple, small notebook, as it is cheap, portable and easily modifiable to my needs.

• Carry it around, everywhere. No matter what system you use, it should be very easy to carry around, and easy to jot down ideas quickly. You need to carry it wherever you go, including to bed, in stores, if you’re hospitalized, wherever.

• Jot down ideas immediately. Don’t wait until later. You’ll forget. Even if you don’t forget, your mind will waste precious CPU cycles trying to remember, instead of focusing on what you’re doing at this moment.

• Once you get back to your computer, or wherever you keep your next-action lists, process your notes immediately. If you just write your ideas down, but don’t actually transfer them to your action system, it’s not worth the effort. The ideas and tasks you write down have to actually be acted upon, or at least decided upon (you might decide to ditch it), otherwise your system won’t work. Your mind will keep that stuff in its active RAM, because it knows that writing the stuff down won’t help you remember it later.

• Don’t use your capture system as your action system. This will be a point of hot debate among GTDers, because some like to use their Moleskines and PDAs as both their capture and action systems. But let me clarify: if you use one part of the Moleskine, for example, for capture, and another part (perhaps marked with tabs) for your next-action and project lists, that’s fine. Just don’t mix them up. If you write down stuff on a list as capture, and then use that same list for your to-do list, you’ll run into problems. Things will be confusing, for one, because the list is just in order of capture. You will also not have things broken into context, which means you will be constantly sorting through different types of actions that you can’t actually act upon right now. And over time, the stuff you still need to do will be several pages up into your notes, meaning you’ll have to constantly flip back through your capture notes to find out what you need to do.

• Use tools you love. Some people love the texture of the Moleskine notebooks, and have a favorite pen that feels great in their hand and rolls beautifully on the paper. Others enjoy the technology of the PDA. Just choose something you enjoy using -- you’ll be more likely to use it.

• If you slip up, just start again. Sometimes we forget about our capture system, or get too busy. It happens to all of us. Don’t beat yourself up, or just abandon the system. It works. You just need to get started again. Perhaps try a new system, but just start.