This guide is just to give a brief jumpstart or reference to anyone interested in running a Vanguard in endgame PvE, or advice for existing Vanguard DPS that are familiar with their class. The guide is based on personal experience.

Specializations
I am listing the other options as well, but only the first three are mentioned later.

Tactics - 8/36/2 (Preferred)
Assault - 4/6/36 (Preferred)
Assault - 8/7/31 (Still like this one though)

Assault - 5/5/36*
*I haven't really used this spec much, but it may do just as well as the other assault spec.

Here's a link to another tactics and assault guide.
http://www.swtor.com/community/showthread.php?t=713289

Going Away Soon
Hybrid - 2/22/22* or 8/22/16*
*I never really got used to these specs, but I keep hearing and reading that they are still good.

For those wanting to give Hybrid a try.
http://swtorboard.org/2013/11/15/vanguard-powertech-dps/

Official announcement for upcoming patch 2.6:
swtor patch notes

TaitWatson wrote:

Pulse Generator now requires High Energy Cell to be active.

Specs Based on Encounter
The following list details which specialization is best suited for each encounter to produce the highest DPS. Some choices depend on your role in the fight or group composition, for example if you're kiting Raptus or not during the Dread Council fight.

Note: Just because one spec is better suited for an encounter than another doesn't mean you have to play it, especially if you're not familiar with more than one spec. The spec that's better for the encounter isn't any good if you don't know how to play it as well as another.

Dread Fortress

Nefra - Assault
My highest is with assault, though tactics is still very close. Assault can help if your group is low on cleanses though.

Draxus - Either
I like Tactics , but they both are good. Both specs have lots of aoe, just in a different form.

Grob'thok - Either
Again, I prefer Tactics for this one. Assault would probably be a bit easier though because everything is used on the move and does not suffer from pipe smash. Tactics still works though because Pulse Cannon is your only channel, so you can save Hold The Line for that moment.

Corruptor Zero - Assault
I really like assault better for this one, and makes it easier to get the attention of the silver adds so that the healers don't get hit. Both are still good though, so it is just a personal preference.

Brontes - Assault
I greatly favor assault for this one. Both specs are very good for the majority of the fight, but in the last phase, she is constantly moving and is often very difficult to use pulse cannon to its fullest.

Dread Palace

Bestia - Tactics

Tyrans - Assault
Your DoT's tick while you run away, and you have 15% protection from the DoT.

Calphayus - Tactics

Raptus - Tactics

Dread Council - If kiting Raptus Assault ; if on Calphayus Assault ; otherwise Tactics .  


Gearing

• Augments: Use Reflex.

• Critical Rating: I have 62, which is just one enhancement. I have seen someone mention getting the ear ring for the crit and the rest power though. I have not tried this yet, but one mod and enhancement would get close to that (two enhancements or two mods work too).

• Accuracy Rating: Around 430 is what I would guess, with the goal of trying to get as close to 110% without going tooo far over. A little over or under is good. A rating of 376 gives you 109.27%. For full 78 gear, you should be at 470 rating (110.43%). Replacing just one enhancement drops you down to that 376 level.

• Power/Surge: These come after you've obtained the desired critical rating and accuracy rating. Fill what's left with these stats. I have a 470 surge rating (72.96%) and 1568 power.

• Relics: I really like the Focused Retribution and Serendipitous Assault combo. Boundless Ages isn't bad though, especially if you happen to come across a boss that needs controlled burst like Raptus's challenges. Those challenges seem to be lined up with that relic cooldown.

Rotations

Tactics :

Always start the fight with 3 stacks of Pulse Generator and pre-load Shoulder Cannon (SC).

I use my adrenal, Battle Focus, and relic if equipped while I run in.

Gut > Pulse Cannon > Fire Pulse > SC > Stockstrike > SC > High Impact Bolt > SC > Ion Pulse > SC > IP > SC > IP > SC > IP > SC

By this time, Gut should just about be ready to use again, and Pulse Cannon about finished.

Only ever use High Impact Bolt if you have the buff from Stockstrike, and use Stockstrike if you have the buff from Fire Pulse/Ion Pulse.

Make sure Gut is always active (sometimes difficult with those pesky slingers and scoundrels), and use Pulse Cannon every cooldown (stacks should not be an issue, but make sure you have 3).

Looks good! I don't have much to add as I haven't ever seriously DPS'd on my Vanguard (serious meaning I wasn't wearing tank gear while doing it).

Btw I'm making you VG DPS Mentor so you get a nice tag to your thread. I will do the mentor thingy properly after I get home from vacation.