Continued from here.
Lord Gusorio rubbed his left knee, just above the spot where the wooden leg began. "Yes, it was against the dragon Grondsvettir that I lost my leg. It was our last delve into the dungeon, and for the most part it went as planned. I didn't intend to let the dragon feast on my left foot as its last meal, but we came away from that battle with enough wealth for me to complete this castle, and for my companions to retire comfortably."
The grizzled baron pauses to have his valet refill his mead cup. He takes a long pull and then looks into the hearth fire. "We were just about as prepared as we could have been against old Grondsvettir. We had all the potions and scrolls we thought we'd need. Aldarus was wielding the dragon-slaying sword Gram. Rashni had her ring of invisibility and winged boots. Garus had memorized all the right spells. We'd scouted out the lair while the wyrm was out hunting, and thought we knew exactly the right place to take it on.
"Not everything went well in that fight, but because of that planning, we managed to pull through. And the dragon is no more."
So many people think of combat as the heart of D&D. And I do admit, it's quite fun. You're risking your character's life against wicked villains and fearsome monsters. It comes down to the luck of the dice, but the odds can be stacked in your favor. Careful scouting can be one way to do that. Getting all the information one can about the creatures to be faced (if known), about the layout of the dungeon (and choosing the spot to fight that's best for you), and planning some tactics before hand can help out even if the dice are being cruel.
I likely don't need to say too much more about this sort of mission. It seems to be what most folks expect and plan for when they enter the dungeon. Sleep and Fire Ball spells can end lots of fights quickly, so Magic-Users tend to prepare those spells 'just in case' on many dungeon delves anyway. Fighters are there pretty much just for the fights.
Because the combat rules are some of the most spelled out rules in the game (even in fairly rules light versions of D&D like Basic), it's an area that's easy to get a handle on. But there are still some pointers that adventuring parties should keep in mind when going into the dungeon intending to pick a fight.
Power in Numbers: Don't scrimp on hiring men-at-arms or retainers to join an expedition when you're sure there's going to be combat. They might just get in the way or tip off the monsters on a scouting or fact-finding mission, but when you're ready to tackle some monster or other, they provide extra offense (even if their chances to hit aren't great, you're still rolling attack dice more often, and that's always a good thing), extra defense (monster attacks get spread around), and if victorious extra carrying capacity to haul out more loot.
Pick Your Battles: Often a party ventures forth into a dungeon ready to take on whatever monsters they meet. But in a Megadungeon setting, there may be many monsters that don't need to be faced. Friendly or indifferent reactions from some monsters can be used to your advantage. Either try to get their help against some other hostile creatures, or just leave them be. Hostile monsters with no treasure should be avoided as much as possible, as well. Again, try to avoid those random encounters. They'll wear the party down before the fight you want to face, and after you're finished with that fight you'll want to get out of the dungeon as soon as possible with that loot anyway.
Know When Enough is Enough: If a group of creatures break morale and run, don't pursue unless they're running away with something valuable. If you've come up victorious in a hard fought battle, but are low on hit points, spells, and magic item uses, don't push on to that 'one more room.' Head back out, heal up, and rearm and regroup. Yeah, that means at low levels, a smart party may want to do that after every encounter. Well, it may not be fun for all, but it works.
Always Be Prepared: In certain versions of the game, or certain campaign worlds, potions and scrolls can be easily purchased. Of course healing magics are nice, but also consider things like scrolls of protective spells like Shield or Protection from Arrows, potions of growth, giant strength and heroism (nice boosts for the Fighter-types), and any of the Protection scrolls if you're up against that sort of monster. If you've chosen the battle ground and will be instigating the fight, use these before the throw-down, so you don't waste valuable combat rounds buffing up when you could be swinging swords or casting offensive magics.