Is your wiring starting to look like this? Bunches of wires and no clue what they belong to?

A simple and cheap solution is to buy a bag of colored zip ties, then match up your installed components with their wires, and color-coordinate with the zipties. I pulled them tight so just the ziptie head is left behind:

The example below is all orange zipties belong to my gerbing wiring. I have an orange ziptie on the negative lead, the positive lead, the relay and then another one at the other end near the controllers. I also put one midway on the entire length of wiring. Very useful for quick identification of what's what, from either the battery side or the component side. I also make it a point to mark the in-line fuses. (Blue's belong to my EC driving lights)

Its easiest if you do this from the start of any wiring project, instead of waiting like me till you had to trace everything. I could have gone with smaller zipties... but I used what I had on hand. I'll get some smaller ones and change them out.