Handling laundry in a building where machines are often occupied

The shared laundry room in my building has two machines and no booking system. I carry a basket downstairs only to discover both in use, sometimes with someone's finished load sitting inside. I don't want to become the resident who lectures everyone about laundry etiquette. Has anyone found a routine that makes this less annoying—off-peak hours, a quick check before sorting, or an informal schedule with neighbors? I'd rather solve my own logistics than start a hallway dispute.