Cable markers are an easy solution. Cable markers come in many varieties, including pre-printed labels, blank labels that you can write on, and printable labels that can be customized on a label printer. There are many types of cable markers, including adhesive wraps, ties, or clips if you need to be able to easily remove and replace them. For a guaranteed non-slip, clean look, you can even use printed heat shrink for the labeling of cables and wires.