Bad example. That doesn’t look very realistic.
Smooth shading is missing from parts of the coutch and chair, showing the flat shaded mesh. No furniture has so flat surfaces (seat parts) unless it’s a piece of plywood, and they’re not so precisely positioned. Same goes for positioning the furniture. The image is too noisy. Picture frames are empty. Whoever decorated that room didn’t put a single thought for sound quality, which is very realistic unfortunately, not many do.
Getting a realistic result comes from every step that is taken to get to the final image. From planning the area, sketches, composition to modeling, lighting, materials, texturing, all the way to positioning the camera, framing, rendering and post processing.
Tutorials? Here’s one.