Use a non-adhesive mounting method if possible. Good options mentioned were:

• sandwiching the strips between layers in a floating frame or cut card-stock guide so the film is held in place by the frame itself
• supporting the strips with nylon sewing thread or thin monofilament run through the sprocket holes
• using photo corners or a low-tack archival mounting tape only if needed

Avoid ordinary Scotch tape, since it can leave residue and may damage the film when removed.

For preservation, constant light is not ideal. A backlit display will likely shorten the life of the film, and direct sunlight is especially harmful. If the film has collectible or archival value, display it with as little light and heat as possible, and expect a lit display to be temporary rather than permanent.

Best practice: keep it out of direct sunlight, in a shaded, stable room, and avoid excessive warmth. A warm room in the shade is better than sunlight, but cooler and more stable conditions are preferable.