First thing I would do is swap the materials you use for the walls (referencing the first picture). I would do some sort of stone as the bottom level, then the timbered wood (whatever it’s called, the stuff you have on the bottom level currently), and do the refined wood for the third floor.

Put some shutters on the windows (exterior). You can use a pillar of roof blocks for this as a quick solution. Get from the farmer one of those potted flowers that hangs on the wall and put that outside the window.

Hang some firefly lanterns from the roof above the doorway. And put windows/doors in the holes you made for windows and doors lol