bring a tanking buddy, who can tell you what to do and if you are doing it wrong.
Ignore all the idiots, try to find the ones in chat trying to help you.
If you have done that for a week or two, you should have enough confidence in what you are doing, to not feel bad about the idiots, who always try to blame everything on the tank.
And then its just finding the other group players and talk about how to improve the group performance (including yours) and ignoring/kicking everyone, who trys to use lfr for his daily testosteron kick.