This may be the most important step you take toward getting your home ready to sell. For a home to live up to the "move-in condition" description, it has to be clean.
If you already keep a clean house, simply keep up the good work, checking to make sure you don't overlook little-used closets and other nooks and crannies that aren't part of your weekly routine. This needs to be a deep cleaning.
For the rest of us, it's time to get serious. Start at the top (the attic or second-story rooms) and work your way down. Clean ceiling light fixtures first, scrub walls and woodwork and finish with floors. As you work your way from top to bottom, don't leave one area until it is completely clean and then move on. Don't drag dirt from one area back into the place you just cleaned.
Finally, don't underestimate the power of clean windows. Buyers won't walk in and think, "Wow, clean windows!" But, freshly cleaned windows look great from the outside and with the lights on, they sparkle on the inside. And with this method, window cleaning is not all that bad.