Speak with Hulfdan Blackbeard in Ironforge.
Another lost soul looking for guidance, eh? I suppose you want to find a purpose - your purpose. I've seen it a thousand times, another hero looking for work.
Well, today's your lucky day, friend. Hogral's got the cure for your ailment.
Here's what you do: Take this road here up to Ironforge and make your way to the Forlorn Cavern. Once there, locate the thieves' guild and speak with Hulfdan Blackbeard. He'll put you on the road to salvation.