I mean honestly there's not too much expertise involved, it's mostly common sense. It's just that it takes so much longer to do it right at the beginning to ensure its maintainable and ordered rather than just doing it the easy way and hoping that it's someone else's problem by the time someone actually needs to find the other end or replace a cable.

Making your own cables that are the exact length they need to be instead of using preterminated ones and just stuffing the slack into the side of the rack, routing them down the side and through the floor or the cabling trays on the ceiling, standardized naming schemes for labeling devices/ports on either end of cables, documented rack diagrams, etc.