S'mon said:
I don't like the adversarial tone of most of this advice. I much prefer a "how would an orc plausibly defend its lair" article to a "How a GM can use advanced templated orcs to kill PCs" article. I think it's best to focus on tricks a monster might come up with, rather than on how to build the uber monster with the lowest CR per the RAW.
I have to agree. I think the trick is (or at any rate, one of the tricks is) to run a frankly punishing encounter
that the players still find fun. Having enemies hit-and-run the party so that the characters never really get to hit back, or hounding them relentlessly so that the casters can't regain spells are good tactics, but its not that much fun for the players. (Though I do agree with frank, in that I consider camping in the bad guy's lair to be bad tactics on the part of the characters, and so a little relentless hounding is justified there. You can't break into someone's house, loot the living room and kitchen, barricade yourself in the den and sleep the night, and then go upstairs to kill them in the morning.)
I'll post a couple of examples not from a game I ran, but from games where I was the player.
The Grimlock Chimney: This was in a friend of mine's game. (Kestrel, who posts here). We're in a dungeon, fighting grimlocks, and we come to this chimney that's essentially an 80' pit, with a corridor continuing on at the bottom. About halfway up on the other side are a trio of grimlock archers. It was a nightmare, in part because we were a melee-heavy party with one arcane caster who wasn't built for blasting (hey, our fault, but we'd been doing pretty good up until this point), and also because those [bleeping] grimlocks were rolling 20's on every other attack (open rolls too, so no impropriety there). That encounter was a
nightmare, but it was also a blast. We still talk about that chimney, and those [bleeping] grimlocks (and we never refer to them any other way).
The Bullywug Swamp: Years ago in 2e, in my old GM's game, the party of 1st level adventurers set off across a swamp for reasons I can't recall. Honor and glory. We get into some fog, then run afoul of some bullywugs, and the 'wugs are leap charging in with spear attacks, and when they get wounded, leaping out of combat. (Again, 2e, so no AoO's and fog you could see a good 30' in.) What made it cool for me as a player wasn't so much that we were getting our [bleeps] handed to us (which we were), it was the sense that this was
exactly how froggy humanoids would conduct themselves in a swamp. It wasn't just good tactics, it was well-roleplayed tactics.
For my money, I like terrain, weather, and lighting conditions for the wildcards. (Fighting grimlocks is one thing. Fighting grimlocks in a cavern where a goblin shaman repeatedly drops darkness spells to cancel the party's light sources is another.) Advanced monsters and monsters with class levels are kosher, because much like every human being isn't a level one Commoner, neither is every goblin a level one whatever the MM says (warrior?).
It isn't so much about beating the pc's as it is about really making them earn their victories.