^Looks like that staircase goes absolutely nowhere.
If you want to make some room for the staircase to go up to the next level you could simply convert the roof to a polygon, for more, better customization. Just a tip.
I assume you are in the very early stage of modeling. The model is not that bad for a beginner though, and I guess you just used textures on the floor and walls. If you want to take it to the next step and improve it you should adjust materials on objects. On the sofa for example, as I can see it reflects the light that comes from the window as a mirror, and looks unrealistic. You might want to change the finish to matte-like, as it really is glossy at the moment. There are other things I can point out but I do not really feel like going in depth since it is in its early stage as already mentioned.
Also why render the pics in such a low quality?