Tunneling for gold will eventually be your downfall. Gold walls can't be reinforced, so leaving a border of unmined gold won't help - and you'll eventually need all the gold you can lay your greedy little Magic Hand on. If you've reinforced all your walls, these empty gold veins will be the weakest spot in your dungeon, so plan accordingly. Between these empty veins and your dungeon, plan for long corridors with lots of traps and doors, which make a nice barricade between you and whoever wants to destroy your Dungeon Heart. As with the open spaces, you want training rooms or lairs located at the weakest points of your dungeon.

   Keeping your minions in order