When marking up on resistant or dark surfaces, i.e. glass,
laminates, dark veneers it might help to cut up address labels
and first stick these across the intended lines maybe at 1ft
intervals. The marks can then be made on, and the line drawn
across, the labels.
Address labels were chosen, both because they were at hand
and because they're particularly receptive to fine pencil
lines and similar. Unlike say, masking tape.