Put on paint clothes and goggles. Paint will drip on you when painting the ceiling.
Put down drop cloths on the floor beneath the beadboard ceiling.
Clean the ceiling. Wipe down the beadboard with a clean rag and a degreasing cleanser.
Make any repairs to the beadboard. Fill holes or dents in the beadboard with wood putty. Let the putty dry and sand with fine grit sandpaper. Remove the sanding dust with a damp cloth.
Prime the beadboard. Spread latex primer on the beadboard with a paint roller. After spreading primer on the beadboard run a paintbrush between the grooves to remove any paint drips. Give the primer two hours to dry.
Paint the beadboard ceiling with latex paint. Work in small sections at a time. Spread the paint on the beadboard with a paint roller and run the paintbrush between the grooves to remove excess paint. Repeat as necessary, letting each coat of paint dry before applying the next.