Prep the room.
Take down any artwork and the hardware used to hang them. Fill nail holes and cracks with spackle, let it dry and then sand it until it’s smooth. Remove all switch plates and electrical outlet plates. Don’t forget to put the screws and covers aside for re-installation. Remove all window coverings and light fixtures. If light fixtures cannot be taken down, loosen them, so you can paint behind them, and cover them in plastic.