1. Floating Plants.
2. Driftwood that breaks the surface and provides lots of cover. Java Fern tied to the drift wood.
3. Keep RBP in a large tank and in sufficient numbers.
4. Use a hanging spot light with led bulb so that only columns of light are made in certain sections of the tank, that way most of the tank is dark with just dappled reflected light. This is key I think, because many fish live in and out of cover and not in pure sunlight - unless you have a huge school, and then I think they loose most fear including the fear of light.
5. Paint the back and sides of the tank a dark color.
6. Use power heads/pumps for a little flow here and there.
That's all i could think of.
Hope it helps!