Tape off the areas for the zigzag lines using painter's tape. Measure with a yardstick to ensure the strips of tape are equidistant from each other. Press the edges of the tape with your fingernail to ensure a tight seal against seeping paint.
Pour the paint into a paint pan. Dab the color along the edges of the painter's tape with a small paintbrush. Allow the paint to dry to form a barrier and maintain a straight, unpainted line.
Paint in the rest of the taped-off areas with a larger paintbrush. Allow the paint to dry completely.
Remove the painter's tape from the wall carefully. Tape off other areas for additional zigzag colors or highlights.