You might wanna check out Taugrim's build the "Iron Fist".
General Vanguard guide:
http://taugrim.com/2012/01/04/guide-to-bounty-hunter-powertech-trooper-vanguard-mechanics-and-pvp/Iron Fist:
http://taugrim.com/2012/01/27/iron-fist-25-14-2-pvp-tank-spec-for-swtor-powertech-vanguard/A couple of really good guides on PvP mechanics in SWTOR:
http://taugrim.com/guides/Keybindings:
http://taugrim.com/2011/04/07/guide-to-strafing-movement-and-keybindings/Here are my keybindings:
Don't mind the score.. I've got other pictures of my bindings but I chose this one since I'm using the shared Assault Specialist tree and not Gunnery so it's a bit more relevant to you.
I use the same general layout on all characters and curse the fracking game everytime I create a new toon and have to do this all over again. A = Strafe Left D = Strafe Right W = Move Forward S = Move Backwards
Basics:
1-5 and R = My standard attacks. 3 being the no-cost Hammer Shot. Why 3 and not 1? Well 3 is easier to reach while using A or D to strafe. 1 and 2 are for abilities that "build up" my damage. In this case Charged Bolts (on my Vanguard this is Ion Pulse) and Full Auto (Stockstrike on my Vanguard). They both have a chance to proc High Impact Bolt (on 4). 5 is usually an ability with a CD or something I don't need to press every couple of seconds, here I've got my DoT Incendiary Round. And lastly we've got R for another medium-CD ability, Assault Plastique. Since AP is currently bugged and only hits one target I've also got Sticky Grenade on shift-R. If Sticky will hit 2+ enemies it's always better than AP..
Shift-1 through shift-5: Cooldowns of various sorts that I use almost as soon as they're ready.
Other keys:
B - My AoE key. Commandos has so many AoE abilities I have to use Shift-B and Ctrl-B (didn't use this when this picture was taken) as well. On my Vanguard this is Pulse Cannon.
C - CC breaker
Q - "AoE utility" .. Knockback on a Commando, AoE stun on a Vanguard, Flash Grenade on a Scoundrel, etc
E - Single-target stun
T - Abilities that have the opposite range than what most of my abilities have. Melee for ranged classes and vice versa. On my Vanguard I've got Sticky here since R is used for Interupts on classes that have 'em (which is everyone but Commando!!!)
V - Some sort of utility, in the case of Troopers I've got Stealth Scan here.
G - Multi-option utility. Got Tech Override here which makes my next cast instant. Can be used offensively or defensively. Will probably have Battle Focus here on my Vanguard.
Z and X - Support abilities. As a healer/dps hybrid I've got heals here. On my Vanguard I've got taunt on Z and Grapple on X. Also using Shift-Z (Mass Taunt on Vanguard and Dispel on Commando) and Shift-X (Guard on Vanguard, not currently used on Commando).
Shift-E - CC
Alt-1 through Alt-5 - Pots and relics. Plus Throw Huttball and my mount. Basically things I need to have ready but often saved for the tougher fights.
Alt-+ - My out of combat heal.
Alt-´ - Aggro reduction, not used much in either PvP or PvE so no need to keep it right next to my left hand.
On the left side I've got my buffs which I generally don't need to use while fighting. These require mouse-clicks to use.
Overall I really enjoy PvP in this game. They could buff the Resolve bar a bit cause at the moment it's still way to easy to be chain-stunned and killed. One stun should fill the bar and not only 75% and roots/snares/slows should also add to the bar (only slows/snares/roots which are guaranteed to happen when an ability is used, like Pepple Throw (Telekenetic Throw) but not Assault Specced Plasma Cell procs).
As for rotations in PvP.. There really aren't any. You always need to adapt to a situation and use whatever ability gives you an upper hand. However there are of course abilities that charge up others and those that do more damage and so on.
One general "rule" for Vanguards no matter your spec.. Always, always, always use your taunts to take the pressure of your teammates. And in Huttball don't be afraid to switch to tank stance to Guard the ballcarrier (unless you've got a tank on your team nearby). It will reduce your damage but at the end of the day it'll give the ballcarrier about 50% more health and will really take the edge of any burst the enemy team will do to him/her.
Vanguards have a lot of fun tools to play with in PvP and for me they're way more fun than Commandos. So you made the right choice with your Advanced Class