7) internal wiring.
connected to 5 and 6 really.
Make sure that all your wiring is top notch. There is a LOT of detail here, but most of it only really applies if your not getting the speed you think you should be.
Basically, rule of thumb - fit the faceplate from 1) above, and make sure that everthing flows from there, using decent quality wires.
Again, plugging a phone into each socket in turn and just listening is a good start
