Okay, so if you have a room to clean, that room probably has windows. (If it doesn't, you can have a freebie.) And those windows have windowsills. And you, being the messy person that you are, probably have stuff lying on those windowsills. (If you don't skip to Step 31)
Step 28- The goal is to make the windowsills empty. And clean, but that part's easy.
Step 29- Look at the windowsill. Are there any objects that are definitely garbage? Throw them out. When in doubt, throw it out. If you threw everything out, skip Step 30.
Step 30- Look at the rest of the objects. Anything you don't need? Give it away. Clean everything else and put it on the floor next to your other objects.
Step 31- Now you have empty, dusty windowsills. Take a piece of damp cloth, or paper towel, and wipe the dust off. All of it. You might need to start with something dry, if there's too much dust. You might also need one of those sprayie windex things. When your windowsills are the color of the paint they were painted, stop.