Looks great! My recommendation is for you to add more decorations and more parts to certain models such as tables. Another thing is that you should change the style a bit for the doors and floors. And my last tip is to try and find matching textures for models like the walls and the floor. Keep it up!
Since a lot of city interior have different types of textures and colors inside it I think you should place more onto the walls at the moment. It’s just one material maybe experiment in different materials/colors. I think you have the right mindset going into this project, but perhaps you should add more detail onto the building. Maybe place some clocks, shelves, better lighting, place some office decor on the desk instead of leaving it plain.
The building in the picture is pretty dark I see you have ceiling lights maybe add some light in the building to create a more welcoming feeling, which creates a contrast effect to the rest of the picture. The chairs and desk don’t match the design your going for some office tables have a lighter color to and draws instead of the one you have. Look at some other picture pieces online.
Make sure your building desk reflects the same level of detail as the rest of your build. From the angle and picture you provided it looks like a thin part. Also put more detail in the desk and interior itself. In some cases this would be just fine, I would recommend using a reference picture to help you with getting the details right it’ll help if your losing ideas.
Lastly, I would think about experimenting with the wall texture more as I don’t think it compliments the floor texture you have going, in the image the wall is a more of a brick material and the floor looks like a stone material so experiment with other materials and it’s colours and see what suites your liking.