I don't exactly know the use of pan in electronic music. When should I use pan (other than Left=Right), and how can it be used effectively?
The uses range from simple separation (one instrument left, another right, vocals and percussion centred) to realistic spatial separation to match the real world environment.
Effectiveness is a very subjective point - what I'd suggest is listening to a track by your favourite artist and turning the balance full left and full right to see what is panned either side.
My band is electronic music with rock guitar. The electronic music is very much meant to be a wall to wall background, so we have different layers panned in stages from left to right, and then the guitars are precisely placed left and right with the vocals dead centre, and then additional multitracking on the guitars as needed at different distances and delays from the centreline to give some width.