He's got some excellent tips on talents and gear -- when you're a Warlock in the Arenas, most of your game is basically keeping DoTs up as much as possible, while also trying to protect yourself from a stealthed Rogue or angry Priest. As with most Arena battles, it's a game of timing -- you want your cooldowns to be up and ready at the exact second when the other team is at their weakest. If you can Spell Lock or Fear a healer at the exact moment when their partner is vulnerable to your own offensive cooldowns, then you'll rack up another win.
Interesting stuff. There's lots more to learn, and especially if you're an Arena veteran, there's probably lots more you already know. But things have changed quite a bit from the old BC Arenas, and especially if you're a Warlock, a guide like this is a good place to pick them up again.