As you know marking wood with a pencil has it's drawbacks particularly
when using a heavily grained wood like oak or a dark wood like walnut.
The pencil mark is difficult to see at best. A few years ago I
discovered day-glow orange masking tape. This tape catches you eye and
is great for numbering pieces and or indicating a pencil mark for cutting.

While pretty expensive I seldom use long lengths and a roll will
typically lase a year when I am busy. About $8 per roll. About 3
months ago I had my wife pick up a roll at the hardware store and she
could not believe that the stuff was $8 per roll! Back in December she
assisted me with the airplane project which had countless track saw cuts
on cobalt blue and brushed steel grey plastic laminate. Pencil marks
are very difficult to see on those colors. She saw me use the orange
tape to mark my cuts and she instantly agreed that the orange tale was
worth every penny. She gave an extra roll of orange tape for Christmas.
Woopee.

http://www.flickr.com/photos/lcb1121...in/photostream