Examine each room. Remove enough of the furniture so that you can create a fluid space that makes it easier to maneuver. It will also make it seem bigger. Be minimalistic when you accessorize. Use some neutral colors
Review your décor. Strategically hang artwork that fits the style of the house and enhances the rooms. You might have to move pictures but then make sure you patch the holes and paint over.
Clear all of the unnecessary objects from the kitchen countertops. Think clean, clear and fresh. Clear messages and magnets from refrigerator and put away your blender, coffeemaker and toaster.
In the bathroom, remove all unnecessary items from the vanity. shower stall or commode top. Buy new towels and soap and put those out each morning. Put away what you've used so your bathroom looks and feels fresh and clean. Make sure that toilet, sink and shower are sparkling.
In the bedrooms, use neutral colors and lots of pillows to decorate the bed. Stay away from frilly. Straighten the interior of your closets and get rid of extra stuff. You want those closets to look big and roomy. Get rid of clothes and shoes you no longer wear. This is really like pre-packing.
Paint and touch up your walls. Don't have chipped paint on your trim or smudges on the walls. If you have wallpaper, you might want to consider getting rid of it.
Sometimes, it's worthwhile to hire a professional cleaning company to thoroughly clean, get rid of the cobwebs and make your house shine.