Hang one tall piece at the far end to pull people through, keep anything on side walls narrow and high enough to clear coats and shoulders, and choose calm work for a space people pass quickly.
Hallways are the most neglected walls in a home and the easiest to improve, because almost nothing is competing for attention.
Use the far end. A hallway has one wall you see head-on, at the end. A single tall piece there pulls people down the corridor. This is the one place where a narrow portrait format beats a landscape.
Side walls need restraint. You pass them at arm's length, so large work cannot be seen properly, and it catches shoulders and bags. Either a row of small pieces at equal height, or nothing.
Hang higher than in a living room. Nobody sits down in a hallway. Centre at standing eye level, around 150 to 160 cm from the floor, and clear coat hooks by a good margin.
Light is usually poor. Deep, dark work disappears in a dim hallway. Pale grounds — mist, sand, pale water — hold up in low light and make a narrow space feel wider.
Watch for door swings and radiators. A frame above a radiator gets warm air rising over it all winter, which is hard on paper. Move it sideways rather than up.
A stairwell is the same problem, at an angle. Follow the line of the stairs: each piece's centre sits at the same height above each tread, so the group climbs with you.