What do you feel has improved your tanking most (ignoring builds and equipment this time)? Things like macros, keyboard settings, different methods of pulling etc... These are a few that come to mind... Most are quite obvious and posted in order of what comes to mind...
Face the opponent
With multiple mobs it pays off to get the majority of mobs in front of the tank in order to increase chance of dodge/parry. Reduces damage a fair bit and makes it easier to use Shockwave efficiently.
Use Pitbull addon
Set the healthbar of all raidmembers to a dark grey or similar. If aggro is lost the healthbar will turn bright red, immediately alerting the tank that aggro is lost and where.
Castbar addon
Perhaps someone could help me remember which one it is... Quartz? Its an addon that lets you customize castbars. The idea is to make enemy spells/abilities appear in a large and visible castbar so its not overlooked in the heat of battle. Increases time available to get a spell reflect in, hide, move etc...
Heal self
Make a macro to heal self with bandage. To be used if there is a break between incoming damage.
Startattack macro
Add the line below to (for instance) the devastate hotkey, or even a few more. Especially nice if off-tanking - makes sure you don't just stand there looking stupid doing nothing after the first mob drops.
/startattack
Warbringer macro
On an enemy it will first cast Charge, then cast Intercept. With an enemy targeting someone else it will cast Intervene (I think if Intercept is on CD) or if you target a player will Intervene to them.
/castsequence reset=15 Charge, Intercept
/cast [help] Intervene; [target=targettarget, help] Intervene;
Use trinkets
I know this is not ideal but otherwise I would not be using my trinkets very much, which is especially bad if they can help improve threat / damage. I bind one trinket to each of revenge and shield slam.
macro 1:
/use 13
/cast Revenge
macro 2:
/use 14
/cast Shield Slam