Gravity controls all things, including house dust. To keep from having to go back and clean the floors again, save them for last. Start from the top down in each room, with the cobwebs that accumulate on the walls and in corners. Work your way down to the drapes or blinds, and then the furniture. By this time, your floors have probably picked up a lot more dust than when you started. Finish it off down low, and you won't have to do the floors twice.