The easiest mess to prevent is the one that has not accumulated.

Prevention is almost always cheaper than cleanup, and it is also almost always harder to motivate, because nothing is currently wrong. The five seconds spent putting something away, the minute spent filing the document, the small decision made now, each prevents an hour later. The costs are separated in time, which is why the trade so often gets made the wrong way.

Adopt the rule that anything taking under a minute gets done immediately. It is a small discipline with a large cumulative effect. Most of what becomes a mess passed through a moment where it took no time at all.