Hi rehab, noticed a request for help that had gone unanswered! If this is your first time collecting, the best thing you can do is start with the very basics and see what works for you. So pick an HQ choice you like the look and sound of first. From a competitive standpoint (without going down the route of picking a single member of the Court of the Archon), the Succubus is probably the best option. Good model too. After that, you'll need some troops, and those troops need to be kabalite warriors. There is currently no point whatsoever in even entertaining the idea of wyches. They just do not work in this edition of the game.
Dark Eldar do best when they're riding to war in their very flimsy but very fast transports, so you'll want to make sure your warriors have a way to get around - either in Raiders or Venoms. An HQ choice, ten warriors and a couple of Venoms will come to less than three hundred points. Once you've got those basics, you'll need to see what appeals to you, so the best thing to do is post up a prospective list on the forum and take some constructive criticism on it. Lots of people on here play for all kinds of different reasons, so you should get a reasonable balance between the more competitive builds and the slightly different fun ones. Do keep in mind, though, that whatever people recommend will NOT be easy to play. Dark Eldar have a steep learning curve. Almost vertical against some armies! But if you stick with them, you can have a lot of fun. Plus it makes it all the more satisfying when you win.
Oh, one final tip, which I wish I'd been told - specialise your squads. Do not give them all different weapons just because you can. You want all anti-tank (blasters, heat lances, dark lances) or all anti-infantry. In certain squads (Scourges) you will get one of each weapon. That just means you have to some bits shopping I'm afraid, or buy multiple kits at once. I know this advice comes a bit late, so I don't know if it's still relevant, but I hope it helps!
My other car is a Ravager