Look at your "system", and using the categories in GTD ask yourself what is the corresponding activity that you are doing in your current system. Evaluate how your present practices are working for you by asking yourself what you like, what you don't like, and what's frustrates or discourages you or sends you crying to your pillow.
Then focus on that part of the GTD workflow chart that most approximately maps to your biggest probelm area. Ask yourself, how will this make my work go better for me if I do it the GTD way? Don't assume you need to implement the whole method. You will probably need a system that has working parts for each of the GTD elements and they will need to fit together. It will need to meet your needs, to support your roles, areas of focus within them and your responsibilities. If you don't have a clear sense of them, you might try to find a time to start making an assessment of these (keep it simple). No two people really do GTD the same way and to aspire to do it exactly as described might bog you down more than help you. But, also guard against trying to refine GTD just because you see the possibility. Keep asking yourself, can I meet my needs and still make this simpler or easier? GTD might be the default mode for maximizing simplicity but that might not meet your needs.
The most useful part of GTD for me has been distinguishing between projects and next actions, keeping track of both, and using these lists (and others) rather than the objects themselves to cue my focus. The least helpful has been the A to Z file system, but it has taught me that my original file system was way too complicated.
I would like to relate the practices of two people whose productivity I have long admired and you will see that each has some GTD elements in it.
One very organized and productive man I knew had
an at home and an at office system. At home, he had a big comfy chair, a TV table, a little stand with paper and envelopes next to the chair, and about 10 plastic file boxes that he kept lined up behind a couch (these were labelled friends, family, financial, his name (personal records), interests and hobbies, houses and cars) and a brief case. "In box " was the TV tray, which doubled as his desk. "In" was brought to empty as quickly as a paper was dropped on it se (unless he was physically not present). He had an address book, a datebook, scissors, stapler, stamps, pens and pencils and scotch tape in the brief case. At the office he had a real "in box" for messages and mail, a desk, and cabinets labeled by year and then subjects within each year. His secretary was mainly a typist, a researcher and file returner/file puller. Every so many years he culled the earliest year or two and what he decided to keep he just added to the earliest year that he had not yet culled. At all times he had two lists on the back of an envelope, his projects and his specific tasks (including the grocery list, memos to draft, stuff to tell people, if ti was a lot of stuff he noted a reference to a file). He crossed off and added as he went through the mail, talked on the phone or met with people in his office (he was a CEO for a medium-sized newspaper). When the envelope was too full, he re-wrote what remained on the list on the back of another envelope and threw out the old one. When he finished an important project he noted it on his calandar and filed the support materials by subject in the current year.
Another of the most organized and productive people I know, has four desks. One is for his intellectual work and it has book shelves and files surrounding it on the topics in his field. He is an art historian, so this is massive. Current projects have vertical file boxes on the desk. Some projects have more than one box. He has his computer here because he only uses it for that kind of writing and research. Another desk is for personal correspondence and it has address books, stationary and a file of folders with names of friends and family at hand's reach, and a little typewriter. What needs to be answered or is in process resides in an active vertical file on that little desk. The other is a big desk and it is for financial matters and has bills, investment, credit files, etc. right at hand. In the financial area he has a cabinet for house stuff. He owns two houses, and has helped to manage others. Each house has a drawer or part of a drawer with things like instructions for the lawn mower or the diagram for the circuits in that house. I would not like tha fact that he has in with this reference material on lawn mowers in general and circuit breakers in general, but it is his file, not mine. The last desk is currently the dining room table and next to it is a mobile file for health matters (he sees a lot of specialists), the calendar is on the wall along with social and business phone lists, and fliers for events that he may attend are in a vertical box by topic or place (lectures, shows, Palo Alto ). Each desk generates its own list and he carries these around. This gentleman is 86 years old and has used this system (except the health desk) for at least 50 years.
I will spare you a description of my own adaptation of GTD because I am still not working it systematically (or systematically working it), but next action by next action I am making progress. The beauty of the GTD paradigm is that you can fix your implementation problems by using the paradigm.