Raid Combat
The day has finally come. You have your raiding armor with enchants and gems, new weapons, just enough pots and food to get you by, you've gotten four suckers to carry you through the Karazhan key quest line, and now you and your guild stand outside Karazhan waiting for those other lazy raiders to receive their summons, too (you didn't actually fly/ride there yourself, did you?). It is now time for all that preparation to pay off. As a rogue in a raid you only have one job: kill stuff. That being the case let’s get right down to it and deal with raid combat.

Trash Mobs
Trash is pretty much the same everywhere. So how do you make the best use of those 20 some rogue skills you have? Well, you throw most of them away.
Opener - Cheap Shot if possible, Sinister Strike if not. If you don't manage to stealth before you're in combat don't worry about it, just Sinister Strike and go.
Middle - After Cheap Shot or a couple of Sinister Strike hit Slice and Dice. Keep Slice and Dice up the whole time and spam Sinister Strike.
Finishers - Keep Slice and Dice up, everything else is secondary. If you get 5 spare combo points hit Rupture. If the target is immune to Rupture, or will die soon, then hit Eviscerate.
Bosses
Boss fights will vary and you should listen to your raid leader over this guide (up until the nth time you wipe and they don't make any changes).
Opener - Screw it. They're immune to Cheap Shot and Garrote requires positioning if they aren't immune to it too, so it isn't worth the effort. Don't even stealth, just run in and hit Sinister Strike when DPS is called for.
Middle - Get 4-5 combo points before your first Slice and Dice, it helps both with early aggro and keeping Slice and Dice going over long periods. Spam Sinister Strike.
Finishers - Get into this rotation: 4 Combo Points - Slice and Dice, 5 Combo Points - Rupture, 4 Combo Points - Slice and Dice. If you find you’re wasting combo points then feel free to shake it up a bit, but keep Slice and Dice up the whole time. If the target is immune to Rupture then hit Eviscerate.
Cooldowns - Bosses are the best time to use your cooldowns. Sure, you could use them on trash but then you have to watch it for the next time you can use, make sure it isn't cooling down when a boss fight starts, and hope you don't need it to live should something go wrong with the next pull. Easier to just save them for bosses and emergencies. Use your DPS boosting cooldowns anytime after the final boss is between 25% and 50% health. Too soon and you may pull aggro (though you might be able to use them twice on long boss fights if you use them earlier), too late and the boss will die before you've made full use of your cooldown. Don't forget any trinkets with a Use function you may have.
Aggro
Your aggro issues are your own, it all depends on you and your tanks. Use Feint as needed, Vanish if aggro is gained and a single Feint doesn't get rid of it, Evasion and hit the Escape key if you aggro before Vanish is ready again. If aggro happens a lot to you and other DPS, the tank has issues. If it happens a lot to just you, guess what.

Hot Keys
In the end you only really need the following skills on your hot keys. Any other skill will either go unused or cause you to be pro-active, and we don't want that. Feel free to add your consumables, too.
Cheap Shot
Sinister Strike
Slice and Dice
Rupture
Eviscerate or Envenom
Adrenalin Rush
Blade Flurry
Feint
Vanish
Evasion