These are really nice quests, i recomend just doing them, or leaving them off to the side and when you find them walk up to them. They aren't really meant to be time consuming. Just keep trying!
The Wizard City ones are usually somewhere around a corner, where you wouldn't expect it.
The Krokotopia ones are usually out in the open if you walk in its direction
The Marleybone ones are well hidden, except a few
The Mooshu ones are out in the open, but they blend in a little bit.
The Dragonspyre ones feel impossible to find. I just don't do those.
The Celestia and Zafaria ones are exactly like Dragonspyre.
