Clearing out a room is the easy part. Most people manage that on a free Saturday and feel better for it. The difficulty arrives six weeks later, when the surfaces have filled again and nothing has really changed. That gap, between a tidy room and a room that stays tidy, is what these guides are about.
The common cause is storage that fights the way a household actually moves. Things get put down where they are used, not where they are supposed to live. If the two are far apart, the system loses, every time. So the advice here starts from habits rather than containers, and the containers come second.
None of this needs a shopping trip. The jobs below are done with what most homes already have, and each one notes the point where buying something genuinely helps rather than simply moving the problem into a nicer box.