GTD organizational categories are typically implemented using Lists. A list contains a set of reminders with some similar characteristics that allows you to keep track of the total inventory of things that have called your attention, have your interest or to which you have already made a commitment.

Each list has a specific function and well-defined limits, so that it cannot contain elements of a different nature. From an organizational point of view, all the things that need follow-up in your personal and professional life can be grouped into seven fundamental lists:

• Next Actions: List of actions you need to perform as soon as possible. It is advisable to divide it into smaller lists according to the contexts in which the actions need to be done (home, office, computer, calls, etc.).
• Calendar: List of actions that you need to carry out on a specific date.
• Waiting For: List of tasks that you have delegated to other people or entities.
• Reference Material: This list is not about actions, but rather information you need to store because it is useful or interesting. It is recommended to classify this information by categories for faster access.
• Someday/Maybe: List of things that you don’t know if you have to do, or that you don’t need to do right now. You need to review this list regularly in order to decide if you need to act upon any of its items.
• Projects: List of all your open loops, which you should check often to ensure you always have action steps defined to get closer to the desired outcomes.
• Project Support Material: It is the reference material associated with your active projects, which you need to have at hand to manage them correctly and make the appropriate decisions about them.