A spotless home makes a strong impression on a buyer. While some level of dirt and clutter is endemic to life in the home, the fact is that the less "lived in" your home looks, the better it will show to buyers.
Consider a furnished model in a new home development - the furnishings and appointments give the look of a finished home - without the wear and tear of actual occupancy. Try to come as close to that level as possible - you'll notice the difference in your sales effort.
Kitchens and baths.
Clean all kitchens and baths thoroughly and keep these areas spotless during the selling period.
Rugs and floors.
Shampoo rugs and vacuum frequently during the selling period. Consider refinishing stained or discolored wood floors.
Wash all windows and keep these clean during the selling period. Wash all screens.
Cut down on clutter.
Consider removing some furnishings and personal possessions if any rooms seem cluttered (you can rent a storage space if you need someplace to put excess items). Clean out messy closets. Tidy up children's rooms and play areas and try to keep these areas clean during the selling period. Impress upon your children the importance of cleaning up after play sessions.
Garage and basement.
Clean out the garage and basement. Organize stored items neatly and remove clutter. Sweep both areas clean.
Clean up outside.
Clean up outside areas. Neatly store any ladders, lawnmowers, or other tools and equipment. Make sure that bicycles and children's toys are stored in an appropriate place. Wash the exterior of the home is your siding is dirty.
Check your landscaping.
Make sure your yard is well tended. Keep the grass neatly mowed and edged. Check your shrubs and plantings to see if they need to be weeded or trimmed.
Maintain a fresh, pleasant scent in the home.
Purchase some potpourri or scented candles to use when the home is shown. Consider keeping firewood on hand during the winter if your home has a fireplace.
Hire a Professional
Making sure your home is clean is a crucial step in the marketing process. It's also a very time-consuming process - one that many people don't have the time or motivation to tackle properly. Hiring a cleaning service is almost certainly worth the cost if you don't have the time to do the work yourself. It may even make sense to arrange for regular cleanings during the selling period.