Set old newspapers down on the ground beneath the wall or walls to be painted. Cover the entire surrounding floor area to reduce the chance of paint splattering onto the floor. Use tape to hold the newspaper in place.
Wipe the walls down with a tack cloth or dry rag to remove any dust or residue.
Pour some water into a large bowl, 3 cups or so for starters.
Open a can of white latex paint and stir it with a paint stir stick, per manufacturer's recommendations. Pour approximately 1/3 the amount of paint into the bowl as you have water; exact measurements are not necessary.
Stir the water and paint mixture thoroughly with a paint brush.
Apply the mixture to the walls with the paintbrush, working in one small area at a time. Brush strokes can be random; the key is to work quickly. Continually stir the white wash solution as you redip the brush into it to ensure adequate paint coverage.
Rub the excess wash solution off the walls with a dry rag as you work in each area. Rub in various directions to create different effects on the walls.
Continue painting the walls with white wash and rubbing them down as you move along until the entire area is painted. Allow paint to dry thoroughly.