I just finished making this guide for Tanks! This might not be the fastest way, but its pretty fast! You will be killing elementals inside Tample of the Jade Serpent its more than 6 000 000 XP / hour, soo if u hate doing quests or sick from getting same 2 - 4 instances over and over again this might just be best for you ( also doing instances is less than 6 000 000 XP / hour ) Soo feel free to check it out!
Here it is: youtube.com/watch?v=XYc-kj-Y1iA&feature=plcp
PS my intention here is to HELP, not anything else.
Hope you enjoy!