Likan Wolfsheim wrote:
Dark Eldar is one of the most fun armies in the game, imo. Hell, half my troops are still Wyches and Hellions are they're doing better than ever, despite the changes to CC. As has been stated they are extremely unforgiving and the moment you make a single, slight mistake (in any phase, from an unwise usage of your Dark Lances to moving a little bit in the wrong direction in the movement phase) it may very well cost you the game. There are probably going to be points repeated from previous posts, but I'll give my rundown of what DE is like:

-You need to win the game during the first and second turn.
Now I don't mean that the game needs to literally be over by turn 2, but you damn well need to have the enemy's fate sealed. Deployment, and the first two turns are when you need to lash out at the enemy. Go right for the throat and keep them on the defensive for the rest of the game. In particular it's the early movement phases that'll decide the game: with all the mobility of DE you can easily pick where the firefights happen and where the assaults occur.

Your best defence is a defence-ignoring offence
It's been stated to death here: DE are glass cannons and have very little defensive ability. Never get put on the defensive. We have the skills of Space Marines with the defences of guardsmen (and we don't have the numbers to take the horrific number of casualties that IG can take). Furthermore our vehicles are made out of paper. There is nobody who plays the defensive game worse than us. When things go bad other armies can castle up and weather the storm, but DE cannot. However, pretty much every weapon DE brings to the table ignores the enemy's defences in one way or another. Be it the 4+ poison of splinter weapons, the AP2 of disintegration cannons, or Lances. AV14 is never a problem, nor high Toughness, and even 3+/2+ armour saves are easy to ignore with the right weapons--or we can simply drown them in shots. All those defensive measure that the opponent pays a premium for go to waste against DE's insidious tools.

Your objective is to kill.
Most of the games are objective based, sure. Do you know who's really bad at camping in one place and holding back the enemy? Pretty much every Dark Eldar unit. Abandon any notion of taking and holding objectives early in the game. Every last unit in your army must be brought to bear against the enemy and be entirely focused on gutting the opposition. A tabled enemy army can't score, after all. If the enemy is not tabled but crippled then it will be an easy matter to zoom a few troops to some objectives and ensure victory. If the enemy isn't even crippled at that point then you've probably lost--their firepower will be blowing the last of your boats off the table and your frail troops' bodies will be ground 'neath ceramite boots.

Play to Win
It doesn't matter if your list is casual, semi-competitive, or competitive--it cannot be played casually and have good results. Regardless of what list you're using and its competitiveness, success with DE requires an aggressive, cutthroat approach to the game. You need need to hit every pressure point, stab every weak point, and tear into the soft underbelly of the enemy army like a half-starved wolf rending apart a hapless squirrel in a crimson, visceral shower of predatory malevolence. Every dirty trick and every low blow must be taken (within the scope of the rules, of course). Any notions of honour, fairness, sporting chances, and the like have to be forgone. The DE army has to be a knife that rams right into the heart of the enemy and keeps on twisting. To play DE to its fullest you have to embrace the army's maligned character. This does not mean you have to be a jerk when you play DE, but you do need to be a sociopath: you are not at the table to give your opponent a glorious battle, you are there to (politely, to ensure future games) slaughter prey.