Hello everyone.
I've been playing a rogue for a while now (since pre-BC) and I thought I'd share with you all a guide to maximize your PvE DPS.
Talent Build
For PvE you're going to be specced mutilate. It is currently very easy to obtain great daggers for a mutilate build at 80. It takes a lot more commitment to get the correct swords/fists/maces for a combat build.
I use this: Talent Calculator - World of Warcraft
Gear
When you're just starting out, I'd recommend dual Librarian's Paper Cutter's enchanted with Mongoose. It is a 1.3 speed blue dagger and because we're not really looking for stats, this is a great dagger. With these weapons and various blue and epic heroic gear I can push out roughly 1800 DPS.
I'd suggest getting around 200-230 hit rating just starting out. Crit should be around 25% and you should have a haste rating of around 250-300.
As for poisons, you'll want to use Deadly Poison on your main hand and Instant Poison on your off hand.
Ability Rotation
The key to maximizing your DPS is rotation. Without a solid rotation that uses your energy efficiently you'll continue wondering why you're at the bottom of the DPS meters.
The rotation I use is simply:
Opener
Open with Mutilate -> SnD at 2 or 3 CP
Build 5 CP -> Rupture
Main Rotation
Basically you want to keep a 5 point rupture up at all times while maintaining SnD. Because we have Turn the Tables (Talent right next to Mutilate) a simple use of Envenom, even at 1 CP, will return SnD to it's 5 point duration.
The only ability you should ever let drop is Rupture. SnD and Hunger for Blood should be up at all times.
Addons
With a good set of addons your job as a rogue can be simple. I only recommend getting one: Rogue Power Bars. This addon simply displays counter bars for your abilities. You'll want to place the bars close to where you'll be looking at the mob/boss so he doesn't move and you're just standing there watching your counters.
Conclusion
Believe me, just reading this guide will not increase your DPS by an insane amount (unless you were REALLY bad before) but it can help spell some things out for you that you may not have realized. Being a rouge takes practice but soon enough you'll be topping those charts.
If you have any questions or concerns with the way I've explained things, please feel free to post a reply. I'll be happy to address it.