Cover the floor of the room you are working in with a drop cloth to protect the floor from splatters. Tape plastic sheeting to the walls with painter's tape. Make sure you press the painter's tape to the tops of the walls so that you have a clean edge.
Add water to an all-purpose joint compound until it is slightly thin. Pour the compound onto a scrap drywall piece. Dip the brush end of a crow's-foot brush into the thinned-out all-purpose joint compound. Cover the tips of the crow's-foot brush completely and shake off any extra all-purpose joint compound.
Stick the thinned-out all-purpose joint compound on to the ceiling by rotating and dabbing the crow's foot brush randomly across the ceiling. Reload the brush ends of the crow's-foot brush with the thinned-out all-purpose joint compound when needed and apply it to the ceiling.
Allow the ceiling to dry according to the joint compound manufacturer's recommended time. Remove the painter's tape, plastic sheeting and drop cloth once the ceiling is dry.