All cables should run either up or down from their sockets/switches, this is so you will know where it is safe to drill or carry out works in the future, it even helps when positioning a picture.
All wire should be protected by a plastic or metal cover, so that if the wires are disturbed in someway they are protected.
Power and lighting cables should not share the same box as a telephone cable and should be 6 inches apart.
Power and lighting cables should be at least one foot away from aerials to avoid interference.