IT folks are the umpires of the enterprise -- nobody notices them until they screw up. To stretch that metaphor further, network cabling is the playing field of the organization, and people think about network cables about as often as baseball fans consider the blades of grass in left field.
I was talking to an old friend and superb wiring guy the other day who observed that nobody talks about wiring. He's right. Yet wiring is absolutely critical to a reliable network. And wiring problems are among the most difficult to troubleshoot, due to the intermittent issues that poor wiring can cause.
So what's to be done? Plenty. For starters, if you're rewiring an existing building, take the time to pull out the old wiring. It's terrifying to pop open a ceiling tile only to find 30 years of nasty wiring all over the place. I've done that in some buildings and found bundles of thicknet, Cat 3, and coaxial that nobody could identify. It probably tripled the overall effort to troubleshoot wiring issues to the edge.
Another good idea is color coding. It makes plenty of sense at the patch panel and in the datacenter, but it also makes sense at the edge in a different way. Running bulk cable to each box is a no-brainer, but especially if you're wiring for VoIP, put a small colored sticker next to the VoIP port and another next to the data port. In environments where VoIP is handled as a trunk with the phone acting as a switch for the PC, this isn't really relevant, but for other installations it simplifies IT support calls.
In the closets and the back room, make sure to invest in proper cable management and find a wiring contractor that can show you plenty of cabling porn -- pictures of a closet cable waterfall of several hundred drops that looks like a painting, or cable management schemes in dense closets that were obviously difficult to wrangle, but resulted in an easily managed layout. These are the hallmarks of a solid contractor, and the work they do will need to stand the test of time -- it's never a good idea to skimp on this part of the overall plan.