I took your advice and looked at the light source. For one thing, the "time" of the original picture was in the afternoon; I switched it to morning so that the sunlight would be coming better through the dining room windows. I also added a lamp post near those windows.
I also added light colored objects to the room to add contrast with all the darker wood, and to help with distinguishing surfaces.
Still not that bright, but better than before. I think I might trying to add some additional light sources within the room later.