Prepare the room for painting. Place drop cloths or tarps on the floor and remove window coverings, switch plates and outlet covers. Remove furniture or place it in the center of the room and cover with drop cloths. Use painter’s tape to protect windowsills, baseboards, door hinges and the ceiling perimeter, or anything else you don’t want paint on.
Paint doesn’t adhere to dirt, so use a sponge or cloth to wipe down your walls with mild detergent and water, and allow the surface to dry completely. Note: Avoid washing with dishwashing liquid as the lanolin in it can leave a residue and lead to poor paint adhesion. If your walls have cracks, holes or other damage, apply spackling compound with a putty knife. Sand with fine-grit sandpaper once the repair spots have set. Clean off the dust after you have sanded. If your walls have more extensive damage, see the project Patch Holes in Drywall to learn how to make larger repairs.
If you need to make repairs, add an extra day to your plans to give the spackling compound time to dry.