Simple yet profoundly effective, it embodies the radically common sense notion that with a complete and current inventory of all your commitments organized and reviewed in a systematic way, you can focus clearly, view your world from optimal angles, and make trusted choices about what to do (and not do) at any moment.
GTD includes an easy, step-by-step, highly effective method for achieving this relaxed, productive state. It includes:
Capturing anything and everything that has your attention
Defining actionable things discretely into outcomes and concrete next steps
Organizing reminders and information in the most streamlined way, in appropriate categories, based on how and when you need to access them
Keeping current and "on your game" with appropriately frequent reviews of the six horizons of your commitments (purpose, vision, goals, areas of focus, projects, and actions)
Author David Allen also has a blog which has more GTD tips and advice.