I have been playing ADoM for about 8 years already and finally achieved a victory. It wasn't easy for me despite of
good RC-combo and some gifts from RNG.
IMHO key to victory in ADoM is variety of options. Some enemies is better dealt with brute melee force, some are easily dispatched by ranged combat, some weak to spells. That's why I like monks and especially drakeling monks. They are universal, you can rely on unarmed combat and play in martial artist style or become heavy tanked warrior utilizing lvl 13 power to smite your armor up to maximum. Spellcasting is also an option, Darkness and Invisibility is rather easy to master and help a lot in mid-game.
The biggest disadvantage of monks is tough early game. I chose Raven birthsign to help me outrun some nasty enemies at low levels and it really helped me couple of times.
I've started game in SMC (after taking some detour to Black Market - nothing intresting there), it went quite smooth. I equipped some gear with unknown status( two hander, metal girdle, metal boots) to get some PV and damage, but it turned out to be cursed. There was scroll shop in UD (which helped to uncurse two-handed sword) and there was nothing nasty like mixed tension rooms also. I've gained 8 levels there and adamantium long sword with some good shield.
Classic route was taken later Puppy Cave -> DD -> learning Pick Pockets from master thief . There was a neutral altar at PC: 1, so I was able to detect my gear status. Guth'Alak teached me herbalism and gave me PoCC for black druid corpse. At that time I still had had my cursed girdle on me and no scrolls of uncursing, so went to ID to grind for money and potions of water. Got 4 or 5 potions, two levels and some money to train Detect traps from ID, then went back to puppy cave. Issrecht blessed my water and I've decided to precrown(I was like 11-lvl with only black torc generated). After some really tedious time I finally convinced diety in my loyalty, but a cat was killed in a process( cave lion was in dark room and I noticed his death only after slaying him and finding his corpse). I thought after such punch in face from RNG I'll get something like black tome but it were shinning silver bracers! Yay!
Also, I found a ring of fish somewhere and raised my food preservation quite high, so it wasn't bad idea to seek some blinkies in ID and pay a visit to Blup's mom after that. Blink dog was found soon, so I've got TControl from it and some her friend's corpses stashed in BM( I hoped to poolsip wish later, so some precautions had to be made).
Then I went to upper CoC, got a quest for ancient dwarf( slay a jelatinous cube, not too hard), farmed some morgia, moss and stoma in Big Room. This time I wasn't lucky with breeders, had to use green slime instead of my favourite worms, but after hundreds of slain spiders( damn dark elves!) room was pacified. Upped my De, To, Wi, now it was time for Pyramid and Graveyard. With BoW and Detect traps it was a cake walk, got ankh, AMW, gauntlets.
It was too early to dive deeper to CoC(and kill Khelly in this case) so I did some business on the surface. Got Tele wand from VDDL( thanks to 13 lvl class power), visited underwater cave with blessed ring of fish and teleport wand, made Blup happy. Needed some xp to get to lvl 16, so I went to gremlin cave and then to TotHK. Gremlins were easy, but TotHK turned to be huge pain in ass. I had no wand of cold, no cold spells either, so I needed some cooperative Orge Magus, but RNG had no intentions to give me one. There was an altar on level 4 or something, so I converted it and sacced a *lot* of enemies, but due to some bug I haven't received 'absolutely close' message despite of being N= (piety level couldn't be an issue here, crowning after 1 precrowning shouldn't be terribly hard and I literally spent days of game time there saccing all that moves and not neutral). Issrecht was happy but I wasn't, still no orge magus and a lot of time wasted. After some more days finally cold vortex was generated, so I desperately decided to give it a try. Last time I tried to freeze water with vortex it exploded right after descending, so this time I lured spider down, and let him to web tiles near stairs, then descended with the vortex. I wasn't sure that it would help, but it helped, so I lured vortex to lake. There I let it float over water, so I was able to freeze as much water as possible. It worked perfectly and vortex committed suicide as planned, making a frozen bridge. Got platinum ring, next target was Dark Forge. Steel Golems were walking pieces of xp, I had near 50 Dx with BoW and RCT, so my DV was huge. No artifacts has spawned, and I had no AoLS, with high piety it was worth trying to get one. I got doomed 3 or 4 times, had to go to puppy cave altar, only 2 pools left and "What do you wish for?_ ", what a relief! Also gained perm invis there, which helped a lot in ToEF.
I saved Kelly, did all dwarf quests, and dived to deeper CoC. Got water orb (RCT rocks - water breathing helped with rivers, demon slaying - with Snake), now only wall of fire divided me and late game. I took a lot of healing, couple of blessed fireproof blankets, bloated myself with stoma and went to tower. BoW regen is great for drakelings, all this dizzy damage was effectively healed. Invis made me able to lure ACW from temple, and then I dispatched him with trident, with speed of 300 I could run in circles around him. Half game done, time to dive and end the game.
Air temple was a pushover, killed all that moved there for exp. Next stop - cat lord. I had some humanoid slaying ammo, and I was really pissed off with cats in this game, so leaving Cat Lord alive wasn't an option. And it was a really exciting fight as I expected. Cat was lured to upper level, I was able to run at the same pace as this cat, but in melee he ripped me apart like child. So only good tactic was to throw phial in his face and shoot some slaying ammo while he stragglers aimlessly. I've tried to play safe but once he managed to bring me to 50 hp or so. Finally he went down, giving me nice xp boost.
At D:40 I finally saw "truly excited" when entered the level. Thankfully, it was GGV, not GUV one, I cleared it all with relative ease and got writing set(2), ordinary ring, and OMG, 'jet-black axe'! BoW and this great weapon, after this I wan't able to lose even if I wished to. Earth temple was easy, but one thing began to bother me. Out of sudden, I managed to exceed 90 day limit (all that trips from DFG to Puppy Cave, time spent in TotHK), and my heap of 10 SoCRs( 6 from Kelly and 4 from mystic) began to melt.
Mana Temple also was challenging, I lost my last char because of terrible stat drain there, so this time I lured Nuurag from temple with wand of far slaying and kited him using same tactics with phial and slaying ammo.
Next stop - D50. I had no potion of uslessness, no free artifact for me, but with Executor and BoW you just don't need any. At D:50 I read all scrolls of peace, drunk some potions of stats, and recovered from terrible cold using wand of trap creation - 10 fireballs from trap brought me to somewhat normal speed. Destroyed levers with WoD, managed to kill all ballors( including Fisty), got heavily corrupted(balors hit pretty often even with 90+ DV), no scrolls left but gates was closed. One of balors dropped potion of water, so I blanked heap of 4 scrolls of power, wrote 4 SoCR and cleansed myself.
After ascending up to surface, I did white unicorn quest (it wasn't necessary, wrote 2 more SoCR from second set while going to surface and wasn't tainted by Chaos at all) and Left Drakalor Chain.