You just have to be artistic and inventive. If wires are too long and get in the way try running them behind the rom drive and hard drive area's and then back out below where you need them. Try to bend long wires to run along the cases outside edges in the back and avoid blocking fans and things. Get yourself some wire ties you can use to bundle wires together and keep them in order. Any left over wires your not using bundle togther and put them on top of the power supply or top rom drive (the rom drive will stay cooler).