>>1771586
looks alright, I'm not much of a builder let alone interior builder myself
You can try adding minor details like moulding at the top corner of the walls.

If it doesn't get in the way of practicality (depending on what you're making this for), try to not have a room too empty, as it would be in real life so it seems realistic. If a room is simply too large and you can't add more furniture without it looking silly, either make the room smaller or accept that it will look empty.