flexable black wire wrap. then wire tie everything together and out of the way, it does wonders.
if your thinking something a little more slick then there isn't really any good way to do it other than using sheat metal to make smooth inner fenderwells, then just keep everything under them. but thats a lot of work to do, and even more to make it look good.
and remember the odds of having a problem are directly porpotional to the dificulty of fixing that problem.