The chances are you've heard of productivity consultant David Allen's Getting Things Done productivity methodology (and the best-selling book where he describes it in detail.) And even if you haven't heard of it, the chances are even greater that you occasionally use at least a few of its principles to be more productive.

So why not do a lot more with a system that thousands of people use every day to improve their personal productivity?

If you want to be more productive and efficient -- and get more of the things that are important to you done -- here's a quick-start guide to some of the key principles of the GTD system.

The Basics

GTD is a system for organizing your tasks, priorities, and schedule so your day is a lot more manageable. The key is to know not just what you need to do, but what to do next -- and to not need to make decisions about what to work on next (or what you might be forgetting to work on.)

How do you do that? There are five basic steps you'll follow:

1. Capture.

Your first task -- and then your ongoing task -- is to capture everything you need to remember. Ideas, tasks, appointments, meetings, projects, plans, goals.... everything.

How you capture everything is up to you. You can use a legal pad, an app, a day planner, a spreadsheet... how you capture is up to you.

The key is to makes sure whatever method you use actually works for you. I use a legal pad because I'm old and grabbing a mobile device is not instinctive. Just make sure that whatever you use to capture everything is so easy for you to use that you won't think, "That's a pain... I'll write that down later." Your method should fit your preferred workflow; otherwise you quickly stop doing it.

And since once you've written everything "old" down your goal is to capture new items as soon as they pop up, your method has to be super easy to use.

2. Clarify.

Items you capture should be action steps, not concepts. Instead of capturing "work on business plan," write "double-check financials," or "identify three new social media marketing strategies," or "revise executive summary."

Of course that might mean that a big project requires writing down a number of action steps. That's okay; the goal is to look at your list and know exactly what you need to do -not look at your list and need to waste time figuring what you should do.

Bottom line, clarifying means writing down not just a task but the outcome you seek.

3. Organize.

Now it's time to prioritize -- and sort. First decide what needs to get done first. (The answer: less things than you assume.) Then figure out which tasks should go together so they're more efficiently accomplished, like making several phone calls during your commute.

If you struggle to prioritize, think about what task drives the most value. If you're in sales, face time with potential customers is a lot more important than reviewing promotional materials. If you're a manager, spending time with employees is a lot more important than responding to "FYI" emails.

There's a huge difference between "urgent" and important.

4. Reflect.

Now take a look at your entire list. Some things you will see you could easily do right away (even if they're not super important.) Other things won't seem as clear as they should; take the time to break that task down into smaller action steps.

Reflection should occur on a regular basis, partly so you can revise your list but also so you can look for ways you can improve your system. Are you capturing everything? Is what you capture clear, actionable, and outcome-focused? Are you prioritizing as well as you could?

GTD is a process, so see your use of it as a process that can be improved.

5. Engage.

Now it's time to tackle your list. See what is next and do it. And don't let yourself be interrupted; see the task through. The goal isn't to "work on" an item; the goal is to complete an item. That way you can forget about it and focus fully on what is next.

And that's it. The book goes into much greater detail -- and can help develop a system that lets you plan your work and work your plan -- but the basic premise is getting things out of your head and into a methodology that lets you remember, prioritize, and accomplish everything you need to accomplish.

A couple years ago I talked to David, and he said:

"Most people try to use their psyche as their systemic process, which means issues gain importance based on your emotions. I've never met anyone who said they didn't feel a little better if they sat down and made a list. Nothing changes when you write things down except how you engage with your issues: You can be objective and also be creative and intuitive.

"Your head is for having ideas, not holding ideas, and it's certainly not for filing things away. Without exception, you will feel better if you get stuff out of your head."

That's another benefit of GTD. When you're stressed or feeling overwhelmed, write down your challenges. List your problems or concerns.

You'll immediately feel better since you'll realize things aren't as bad as you think. And you'll start to figure out ways to make things better -- because now you won't passively worry. You'll actively solve your problems.

Plus, writing down anything you need to remember ensures you don't have to worry about what you might be forgetting.

That's another stress you just don't need.