The reason a tidy desk does not stay tidy is almost never willpower. It is that half the objects on it have no assigned place, so "tidying" means moving them into a temporarily acceptable pile.
The fix is to sort by how often you touch something, not by what it is. Three tiers.
Tier 1: hourly
Pen, phone, notebook, headphones. These need to be reachable without looking, which means they live on the desk surface, in the open, in a fixed spot.
This is the only tier allowed to occupy the desktop. A Stubbe Solid Walnut Pen Block at $16 or an Ordne Wood Desk Tidy is enough. The constraint matters more than the product: if it does not fit in the tier-1 container, it is not tier 1.
Tier 2: daily to weekly
Chargers, spare cable, sticky notes, the notebook you are not currently using. You need these within arm's reach but not in your eyeline.
Under the desk, or above the screen. This is what under-desk drawers are for — a Glid Hidden Under-Desk Drawer adds a drawer to a desk that never had one. Above the screen, a Hylle Tiered Desk Organizer or a Brett Folding Two-Tier Shelf uses vertical space that was doing nothing.
Tier 3: monthly or less
Manuals, cables for devices you no longer own, the box something came in. These should not be at the desk at all, and the honest answer for most of tier 3 is a different room.
What survives — reference books, archived notebooks — goes somewhere deliberately inconvenient. A Ramme Grid Desktop Bookshelf at the back of the desk works precisely because it is slightly out of reach.
The rule that makes it hold
One in, one out, per container. When a container is full, something leaves — it does not get a second container. This is the part people skip, and it is the only reason the system survives month three.
Start with one tier
Do not reorganize the whole desk on a Sunday. Pick tier 2, because it is the one causing the visible mess, and give it a drawer. Tier 1 sorts itself out once there is somewhere for the overflow to go.