I've been expousing this concept since a little after the new codex came out but I've seen so many lists that rely on only one way of doing damage that I was starting to feel like I was taking crazy pills.BREAK your Opponent with Waves of Abuse
Without getting to much into the specifics of any particular Dark Eldar army build you must plan to hit the enemy in waves of pain. The true first turn alpha strike days are over and more a result of poor listbuild/deployment on your opponents part then anything you have done as a Dark Eldar general. Changes to the new game have moved listbuilds you will find on top tables into a new realm of durability. Plan the waves carefully and unleash with Murder on the mind. Scariness wave, long range Lance wave, heat from the pending and crashing Assault wave, and be sure to pack a wave of Poison in between all the others.