PC Case wires a problem

I've been building custom mod pc's for awhile (nothing too extreme) and I've always had the same problem - tangled up mess of wires. A lot of my systems have clear windows but when you look in you see just a bunch of tangled wires. That is because I tend to put a lot of lights ect. in the case and it adds to the mess of wires. Does anyone have a suggestion to help keep the wires undercontrol and out of site?