Cleaning your home should go beyond the usual weekly or day-to-day cleaning jobs, even if you have to hire someone to do it. It could take all day to complete this job, so you might want to pay for assistance.
Wash the windows inside and out. Rent a pressure washer and spray down sidewalks and the exterior. Recaulk tubs, showers, and sinks. Polish chrome faucets and mirrors.
Yes, you're still living there so it's not going to be absolutely spotless 24/7. But make it a habit to clean up after yourself daily—maybe more than you would normally bother with until the weekend. Vacuum daily instead of weekly. Wax floors, dust furniture, and clean ceiling fan blades and light fixtures. Bleach dingy grout and replace any worn rugs.
Pay special attention to the bathrooms and the kitchen. Hang up fresh towels. Bathroom towels look great when they're fastened with ribbon and bows. Make it a habit to keep the toilet lid closed when it's not in use.
Kitchens are a big selling point for many buyers, so you'll want yours to be as spotless and uncluttered as possible. Don't forget those snoopers—make sure the interior of the fridge is clean and orderly, too.