Wellmet,
Dungeon master for dummies is one of those book that give you a lots of good experiences from older master’s of the game... and yes the Pathfinder Gamemaster Guide is very good. = )
For me IMG (in my game) Dragons love to go where the gold’s and magic is... Nobility, ships at sea and large caravans..., young Dragons raid caravans, meddle age raid ships and yes they use slaves, oups I mean hired monsters or mercenaries, small villain, thief guilds etc...
The old ones raid the kings, and nobility and large kingdoms, with the help of nobility blinded by there lies, and wars or fear... but that is a secret... I best go... Dragons don’t like the chant, that’s the dark of it...
Peace, I go hide !