I main thief, have played 1500 hours as one, and I know of every speedclear and pug-clear tactic for every dungeon path (maybe except HotW, I hate that one), and fractal. I am also aware of most builds, with the exception of mesmer, engineer and necromancer, and I know of the use of consumables, such as performance food, budget food, slaying% potions, alternative sigils, etc.
I am eager to share my knowledge with every newbie out there.