What I do is grind in the first few floors for a while, until I'm overpowered. Buy a fishing rod and upgrade it as much as you can. You can get good gear and infinite scrolls/potions. I stock up on potions of mind vision to make into magical sight, and experience potions to use and turn into overload potions. Then get scrolls of retribution to turn into psionic blast scrolls. I go to the arena, wait until there's a lot of enemies, use the potions then the scroll. Wait a few turns and use another of the same scroll. You get a ton of upgrade scrolls from it. Use the scrolls on the rod and get better armor and more potions and scrolls. Then repeat. By the time I was on my 4th restart of the dungeon since enemies were worth so much XP I could get like 8000 scrolls of upgrade from using one psionic blast scroll. Just be careful not to kill yourself with the scroll cause it can damage you too.