The trick of the game is to keep moving the elements. All you have to do though, is to move the farthest right element all the way to the left (thus shifting all elements one space), periodically. Remember to move the elements before the land dries out, or you lose. It get progressively faster.
@poinsonthewell and sportsyeti: All zones only has one kind of crafting material. If you do not see the one you need in the corresponding crafting level, move around to a different area in that same level range, and see if you pick it up. At least one zone in your crafting level range will have the material you need.
That is simulating a pull that you might accidentally aggro, just as in WoW. The pull setting just determines how many units you attack at once, in cases where you might want AOE dmg (I'm not sure if that exists, I only use a rogue).