The attitude certain tanks have....

[Hoglan]

Wow, as a tank, I feel really bad that people have had such bad experiences.

A couple things I make sure to do:
First, if it is my first time in an instance, I tell the group "Hi! This is my first time, so bare with me." Usually, I find 1 or 2 others that are new.
Second, upon reaching a boss pass gate, I ask "Any tips for this boss?".
Third, mark your targets!
Fourth, keep your eyes open during battle. For peels and adds.

Next, macros. You have to use them as a tank.
My survivability and pulling have improved so much since I have dialed them in.
Here is 1 that I use almost every fight.

Macro 1 - "Pull!"
/micon "Flash"
/ac "Flash" <t>
/wait .25
/ac "Provoke" <t>
/wait .25
/ac "Rampart" <me>
/wait .25
/ac "Convalescence" <me>
/wait .25
/ac "Awareness" <me>
/wait .25
/ac "Sentinel" <me>
/wait .25
/echo Recast Pull!