You start by straightening up your room (you may want to have a pile called "Garage Sale" for those things you are too big for now).
I'll stop by your home once every other week (no special day) and if your room is cleaned up (it doesn't have to be "perfect", just pretty good), then I'll leave you a treat on your bed.
When your home sells, you will receive the "Clean Room Club" award and your name will be put into a drawing for a "Grand Prize". A new Grand Prize winner is announced in January, March, May, July, September, & November.