One irreversible and positive consequence of applying GTD to your life is the fundamental change in the way you listen to people, write down your notes and think about things in general.

This is not something you will notice right after getting started with GTD. It will take weeks, perhaps months, of discipline and practice with the core GTD principles.

David Allen states that two of the most important questions you can ask yourself about anything, are:
1. What is the successful outcome (of this project)?
2. What is the next action (the very next, physical step you can take to make progress on this project)?
Note that a project is not a project in the classical sense of the word but simply a multi-step action in GTD speak.

I’ve found that consistenly applying these two simple but powerful questions (and especially the answers to them!) combined with an acute awareness about how “stuff” is processed and organized into your GTD system, fundamentally alters the way you think, the way you listen, the way you write and perhaps even the way you read, for the better!

I’m no expert but I think it has to do with “programming” your reticular activating system (RAS). I’m simplifying here, but this is an example of your RAS at work: suppose you just bought a new car and you are driving down the highway. Suddenly you notice more cars of the same brand, type and color as your new car than you’ve ever noticed before. This is your RAS working; your focus and attention is subconsciously on the type of car that you’ve been thinking and reading about for months before buying it. Another example: you are, once again subconsciously, using your RAS when you are skipping through articles in a newspaper, or your RSS feeds, scanning for specific keywords that spark your interest. If your mind is on the subject of GTD for instance, all of a sudden you will notice more articles or posts about this subject than ever before. Your RAS is a useful tool for focusing your mind and effectively filtering the essence from all visual and auditory inputs.

Leveraging this knowledge, you can “program” your RAS to think, listen, write and read more effectively and geared completely toward your GTD system. You basically tune your mind or switch it to a certain mode in which the answers to the two questions (What’s the successful outcome? What’s the next action?) are automatically looked for. At first you may find that you need to ask yourself these two questions explicitly, but after a while this becomes an automatic, almost subliminal, process.

I enhance this state of mind even further by being acutely aware of the structure, content and workflow of my personal GTD system. This basically creates another filter in my mind that allows me to effectively distill key ingredients such as actions, projects, someday/maybe items and “waiting for” items from any conversation, from any text or from my own thoughts.
If you know that you are going to process and organize what you hear, read, write or think into your GTD system in the near future, it helps to apply this filter in advance, especially while capturing all of this stuff. See also tricks #4 and #5 in my previous post.

Some examples of how this works in everyday life in order to listen, write and think more effectively:

Listening (also applies to reading)
Much of what you are hearing in a conversation, a phone call or a meeting is irrelevant. If you tune your mind in the way described above, you will soon hear the alarm bells in your head (and learn to respond to them!) whenever a potential action, project, et cetera is mentioned in the conversation. These items form a significant part of the essence of the conversation and will probably have to be captured into your GTD system.
Also, your attitude and behavior is different (more active, more positive, more focused) in a conversation or meeting if you have already determined the successful outcome for yourself and you encourage yourself and others to focus on next actions instead of vague commitments. Even your questions will be more focused and more effective if you have “programmed” your RAS.

No matter if you are writing a proposal or a blog post, your writing will be more effective, structured and to the point if you always (subconsciously) ask yourself what the successful outcome of the blog post or proposal is. You will write more action oriented when you are translating your thoughts to paper if your mind is “tuned in”.
If you’re making notes and your RAS is “programmed” in such a way that you already mark actions, waiting fors, someday/maybes and projects with special symbols or colors almost automatically, it will be a breeze to process and organize these notes later into your GTD system.

Don’t waste your time and mental capacity on ineffective thinking or even worrying. Structure your thinking process, focus your mind, be on the lookout for actionable items, projects, things that other people should do and most all what you are trying to accomplish and what successful accomplishment looks like exactly.
Combine your mental process with thinking on paper, for instance by using mindmaps. Apply the same principles that I mentioned above for Listening and Writing to your thinking as well.