The dungeon finder system is relatively new, but there is already at least one good dungeon leveling guide on the market to help you figure it out
. A good dungeon leveling guide like Dugi's Dungeon Leveling Guide can help you manage your time more efficiently. A dungeon leveling guide should direct you to the dungeon quests that can be done inside the dungeons that are available for your character's level. In particular, Dugi's Dungeon Leveling guide even includes maps for the lower level dungeons, which are a great help because Blizzard never included maps for them in the original game.