Wet saws have a way of washing off the pencil marks you make when cutting tile.

Sharpies are not a great solution because they are so darned permanent.

One solution Bogie has stumbled across for marking tile––and other surfaces––is a Pica Dry construction pen. It has a sheath that protects it from dust and moisture and also has a built-in sharpener. Different colors of graphite lead refills are great for marking on dark or light surfaces, available in water soluable and water resistant versions.