Have a dark corner or hallway? Brighten it up with a decorative mirror.
Neutralize the walls. If any rooms are painted in dark colors, repaint white or beige.
Paint adjacent rooms the same color to make the whole space feel larger.
Fill nicks and holes in walls, and touch up with paint.
Sorry, wood paneling. It’s time. Paint over paneling with a neutral color. To really cover your tracks, use wood filler between panels and paint over the entire thing.
Make sure every switch plate and outlet cover matches and looks brand new.
Wash the windows, inside and out. Repair any holes or tears in screens.
Replace those family portraits with interesting art placed strategically throughout the house. Avoid leaving dead space on walls.