The usual advice like replace the dead light bulbs so broker and customers don't need to stumble thru "dark as the inside of a cow" cellar. Remove the "stuff" or at least have one giant pile of cargo rather than spread around the entire property. Clean the windows, remove "smells" with good old fashion cleaning and rug removal. But one of the biggest "to do's" is ta da..the small leak stain in the dining room which is under the bathroom that had a little hurricane during last tub time bath adventure with the little pirates..I mean kids. Instead of painting the entire ceiling...and you never get the right shade of white so it looks worse....just get some bleach. Put it in a small windex glass cleaner kind of bottle style sprayer. Don't get it in your eyes from the mist as you apply a little bleach right on the discoloration. Do a little, squirt squirt and stop. Do some more tomorrow and leave it alone to dry without saturation or drippage . After four applications or so the stain disappears and you save an entire saturday of painting that ceiling. That full day by Mr Owner could have been used on seventeen other little projects as he begins to look at the place with new eyes..the ones of the buyer. For painting tips and other do it yourself help, visit here!
I watch and use DIY all the time. I get some great hints from them!