Exterior of the House
As with your interior, painting can give you the highest return on your investment. If your house looks faded and tired, buyers will notice immediately. Be smart with your color selection. The house should blend well with the neighborhood, but the color should also blend with the style of the house.
Don't forget about the roof. If it is leaky, repair it before the house is sold. Ask the home inspector if you need to. Don't spend money if it is not necessary.