Depending on your niche's location, it may not have access to ample lighting, meaning the objects inside will be difficult to see. If this is the case, try adding accent lights to your wall compartment. Most people install small, low-watt spotlights inside their niche's ceiling, similar to a museum display. However, you can also install accent lights by:  Gluing a LED strip along the edges of the niche. Placing a tap light inside the niche. Pointing external spotlights at the niche. Unlike accent lights, which just add luminance, pendant lamps serve as both a lighting fixture and an artistic statement. Wired via a hole in the niche's ceiling, these lamps hang down and take up a large amount of space, pulling people's eyes to the area. Depending on your desired aesthetic, try going with a sleek, modern lamp or a more elegant fixture reminiscent of a chandelier. If your wall compartment has enough light already, try adding candles for purely aesthetic reasons. Large, tall candles will create an elegant look reminiscent of religious services and holidays. Small tea lights will create a more romantic display, bathing the area in warm light.

Summary:
Install accent lights to show off the objects inside your niche. Put in a pendant lamp for a more elegant look. Set candles in your niche to create more natural lighting.