Specifically, rock golems and fire elementals. You probably have to be at least level 12 or so to make this work; I waited until level 17 to go to the Black Mountain Clan because I was pursuing other quest lines and cleaning out some sewers. ;) Dog is also a great help.
Strip.
Literally.
For fire elementals, take all armor off your characters. For both golems and fire elementals, remove all good weapons, and preferably all weapons. Notice that there are nearly always handy chests placed right before you get to a golem or elemental---dump your gear here.
My PC's bare hands did more damage to a rock golem than a weapon. If you have a particularly weak character, use yourself as bait. Go turn-based, edge towards the enemy until he spots you and begins to pursue. He will fixate on you to the exclusion of the rest of your party. They are fairly slow, so use your first turn to run away, leading him back through your party, who will then take "free" attacks at him.
Once the golem/elemental is down, re-equip out of the chest and go your merry way until you hit the next encounter with their ilk.

Other viable strategies include:
1. Using throwing weapons, which somehow don't take damage from use.
2. Using guns or bows (mind your ammo)
3. Carrying around extra "throwaway" gear, possibly that you looted off of corpses in the same dungeon, that you can use until it breaks and then discard.
Stripping is by far the most entertaining way to do it, though.

*nod nod* Yep, only you still have to take all good weapons out of your followers' inventories, or they'll re-equip them automatically. You can't talk sense into them :)

At first I used to strip too, until I discovered the disintegrate spell, which made it all incredibly easy. Well, as long as you don't run out of fatigue potions anyway.
Fire elemental? Disintegrate!
Golem? Disintegrate!
Robot-thingy? Disintegrate!
That spell is so good, it almost makes me want to stick to magic only and never try the tech side.

harm, F5, harm, harm ... blue potion, harm, harm ...