Find an area rug and use that ugly stuff for the border around it. Can't change the rods. Take them down and use spring tension rods inside the frame. Velcro a valance to the molding. You can change the knobs or pulls on the doors and drawers and take them with you when you leave.
Plants do well in the moisture.
Bathroom idea works too. Velcro pictures on the refridgerator. Try different arrangements with your furniture. Will make a big difference. Don't put all small in a small room.