Measure the door, not the toran
A toran is sold by its own length, but what matters is the width of the frame you are hanging it on. Measure the outside of the door frame, edge to edge, and pick a toran within five centimetres of that number. Shorter and it floats in the middle with a gap at each end; longer and the ends fold back on themselves and the bells collect in the corners.
For a standard Indian main door — around 90 to 105 cm across the frame — a toran between 90 cm and 110 cm sits correctly. Double doors need the width of both leaves plus the centre gap, measured with the doors closed.
Where the loops actually go
Most torans have a loop at each end and nothing in between. Fix the loops at the top corners of the frame, not on the wall beside it: on the wall the toran hangs away from the door and swings every time it opens. If the toran is heavier at the centre — a large motif, a row of bells — add a third fixing point at the middle of the frame and let the fabric take a shallow curve rather than a deep sag.
Adhesive hooks and what they will not hold
Adhesive hooks hold on sealed wood, glazed tile and painted metal frames, and they do not hold on unsealed plaster, distemper or a dusty surface. Clean the spot with spirit, let it dry, press for thirty seconds and then leave it a full day before hanging anything. A hook loaded within the hour is the most common reason a toran ends up on the floor at four in the morning.
After the festival
Take the toran down the same week. Fabric left on a door through a monsoon absorbs damp from the frame and the dye marks the wood. Coil it loosely into its own bag rather than folding it flat, and keep it out of direct sun — sunlight fades a marigold toran faster than any amount of use.