When entering a dungeon, the first thing to realize is that they are randomly generated, and the random generation algorithm is
stupid. Each dungeon starts off as a series of five north-south hallways with preset locations for the ladders up and down, and then doors and other obstacles are added randomly. If you ever see a corner in a hallway, don't get excited, because it means there's an energy field in place of a wall. (The fact that the system can draw corners yet they don't really exist indicates that this is a bug.)
On each level you should always be aware where the up and down ladders are, because they don't move. On the first level you'll start in the northwest corner of the floor, and the ladder down will be near the south end of the next hallway to the east. It's usually easy to find this first ladder, though on rare occasions you may need to seek out a secret door. (In my experience, every dungeon's floors are fully accessible if you take the time to search out all the secret doors.)
Each pair of dungeon floors features the same set of five enemies. On the first two floors, the enemies are fairly weak. The only one that really deals a lot of damage is the
Bat, though
Giant rats are no pushover either.
Thieves will steal your reserve
Weapons, which tends to be more annoying than effectual. You may want to sell off your extras, or invest in a lot of cheap
Daggers if you have
Weapons you want to keep in your inventory (such as a
Staff or
Triangle). The
Creatures on these two floors are very little threat.