I thought I'd share some things I've learned for dispatching the really dangerous named baddies - namely Ur Khan, Golgor Dhan, and Sherarax. These apply to natural limb games, if you are an artificial limber then kiling these guys is easy.
General tips
Beef up Astr, Dex, Agi, and HP. it's nice to have over 30 for Astr and Dex (over 40 is possible and I have topped 50 once). Agi is best over 20, 30+ is awesome. HP below 200 means hello one-shot death, I prefer 300+ for safety.
Use wands of slow (on them) and haste (on you) I pretty much always get perma haste nowadays - it rocks.
Don't use wands of striking, fireballs, or holy bananas, or mines or backpacks. A pile of backpacks and a well timed wand of striking means an easy kill but it also means good bye goodies, Ur Khan has 4 bottles of ommel urine, Golgor Dhan has 3 SoEA and 3 SoEW, Sherry has scrolls of taming and wands of haste (can;t remeber how many). I think Ur Khan has best loot and Sherarax the worst of the three.
Do use bear traps. Mithril or better. Octiron or adamant bear trap rule and valpurium, well they are fcuking awesome. plant a bunch of them like 4 or so and then lure the baddy over them. Whack away at them until they nail you with a good shot and then teleport away and drink a healing potion. Repeat.
Enjoy your loot!