You can try a reflection sphere capture with a small radius next to your chair. A roughness map is a greyscale texture of your floor. The darker parts are less reflective and the brighter parts are more reflection (or vice versa lol). You can clamp the values to tweak it further. For example, you could decide that the roughest parts will have a value of .75 and the most reflective part will have a value of .25. It will add alot of realism to your floor and look less flat. You can add a subtle normal map too but generally I find the roughness map to be enough.
Just take your diffuse texture and change it to greyscale in photoshop and tweak it and experiment within your ue4 material.
This is an example, a roughness map is the opposite of a specular map. If you already have specular map, plug a one-minus node in front of it and it will invert the colors and become your roughness map.
This is the result of a roughness map, you can see the dust/worn parts on a perfect gold material.
