Marduk: Finally something I think I can help with. (I get a lot of great help here.) I think the strongest thing about Corona is the Sun. If there is an opportunity to let some sunlight in anywhere, then you can take advantage of how beautiful that alone makes things look. Try to accomplish much of the lighting that way. Then I usually add some rectangle lights near ceiling pointing down. I actually have not decided which is better, spheres or rectangles in terms of realism, still looking into that. I keep sky (and Sun) intensities very minimal. And yes using an HDRI light material attached to a Cinema sky is nice too, but still need those fake openings.