That quote is obvious bad advice, just so you know.
I don't think we have a decent leveling guide anywhere on the forums. Leveling is not unduely hard though as a lock, around level 40 you get spec defining goodies that will cement the differences between the specs, after which I would try out the different specs to get to know which you prefer. As for info once you near max level, this forum will help alot, especially the stickies, and I;ve found
WoW Insider pretty useful at times too ( they did a splendid few pieces on leveling in Cata).