An artist called xelptic have posted a few weeks ago a scene called Red Room at the blenderartists.org and along the settings and render time; he was kind enough to share the scene file, with all the settings for YafaRay. This is one of the best resources to learn about a render engine, a sample scene with all the settings ready can really clarify the settings and workflow to create a scene that looks like the red room.
If you want to learn something from this 3d interior scene made by xelptic, recommend you to open the 3d interior scene and make a comparison between the scale of the model and the settings applied by the artist. Before anything, notice the measurements! This is really important, because the settings used for rendering could work with 3d models and 3d scenes in the same or similar scale. But, for bigger or smaller scenes it may result in renderings without the same level of realism.