• Holding down shift and an arrow key will turn you and then move you forward. Of course, this has no effect when pressing the forward arrow key.
• Keep your HP high.  As your HP decreases, you fight less effectively.
• Using magic or killing the leader of a group tends to scare monsters, making them more likely to run away.
• Thieving monsters find it harder to steal gold/items from characters further back in the party.
• Levitation occasionally fails, so even though you may be levitating, you can still take damage from pits.
• Magical flight allows you can use the -/+ keys on the keypad to move up/down. (Yes '-' moves up & '+' moves down)  It CAN still fail over pits.
• All Slimes are 100% Mind resistant.
• Most creatures are highly/fully resistant to any attack form they can innately use.  i.e. Dragons are largely immune to fire, slimes are largely immune to acid.
• The first time you see sporing fungi, run away.  (In fact, you will want to run away from these guys most of the time)
• Make sure you have at least one spell caster in your party who is good at casting resistance spells.  Stone, paralysis & drain Res are some of the most important resistances.  Poison & Disease Res are also very useful.
• Some monsters can only be harmed by companions or certain weapons.
• Teleporters that require magical flight to get to usually take you a number of levels deeper into the dungeon.
• After hitting an extinguish square or anti-magic trap, don't try running through the dungeon without recasting your spells.  If you can't recast them, its often best to head home.
• Collect bunches of: Dusts of Healing, Crystals of Healing, Crystals of Mysticism(Greenies), Scrolls of spells.  The healing items are valuable for healing without using valuable mana, and scrolls of spells are great for restoring mana to your spellcasters.
• It is advisable to keep the stack size for the above items to a reasonable amount, as it is possible for them to get stolen/slimed.  Losing a stack of 1000 crystals of healing is not nice...  Possible stack sizes are:  Crystals of healing is 150;  Dusts of healing - 50;  Scrolls of spells - 10;  Crystals of mysticism - 5.
• When adventuring deep, it is often advised that people carry two sets of greenies, as it is easy for one to get stolen/slimed.(Of course, sometimes both can get done in...)
• When a party kills a monster required for a guild quest, all people with the quest for the monster are completed at the same time.  e.g. 4 warriors can complete the quest to kill the slave driver at once.
• If you get the message 'weapon has no effect!', you need to upgrade your weapon.  For the mean time try and use spells.  It is possible that you may have come across a special monster only hurt by specific weapons or companions.
• Stud square contain monsters that normally dwell on the level below your current one, or stronger monsters from your current level.
• When lost, you can find yourself by holding down Shift-Downarrow.  Your character will pace back and forth and eventually find themselves.
• Anti-Magic squares can be fulled mapped by attempting to cast any spell.  Even trying to cast a combat spell will flag the square as anti-magic.
• Fountains restore health, the blue balls on pillars restore mana.
• Many of the powerful spells cannot be cast while monsters are peaced.  Press Shift-P to pause, press f to initiate the fight, then cast your powerful spell and unpause.
• Restoring spell points at the fountain in the city is far cheaper than restoring HP.
• Try and have characters get a guild crest for all the guilds they are in.  This will make the character much more powerful.

If you are constantly worried about your character getting damaged/killed and you have to frequently retreat from fights, you are probably too deep.