This post was published long before the Mists of Pandara Expansion.
The tips and techniques explained here may be outdated.

Achievements online

OOO the achivements are insidious. Now, not only do you have them in game.. but they’re reflected in the Armory

But take everything with a grain of salt.

For example here’s one of my achievemnts:

ORLY? Lilac… the warlock.. has pickpocketed 82 times? You’re right.. warlocks are totally OP.

There’s also some squirrelyness with AV deaths/kills counting [...]