I have a little secret shame for you: I have no idea how to play pure spellcasters. I mean, seriously. Default fireball is too weak. If you are Wizard or Sorcerer, okay, you can throw may be 4 fireballs, so what? It's still not enough usually to kill someone big, you need to hit it too, but your hits are ridiculous. Yeah, Sorcerer got good heal from spellcasting at early levels, but still. If I'm trying to go in VGT with Gnome Wizard, prepping Dragon Soul, scumming for Mystera, I'm still running out of recources to 3rd floor.
So the only way I discovered for myself to play spellcasters (and these aren't only Mages Guild classes, but also Priests, Monks, Gorgons, Elf/Gnome Tinkers, I also have secret shame about them too, I just can't realize this regenfighting strategy, I need to REVEAL BLACKSPACE to get items, glyphs, monsters, boosters, I can't wait for it) was when I got Avatar's Codex for the first time. Since then all my Wizard/Sorcerer/Bloodmage/Priest/Monk/Gorgon games are like this. (But yeah, Orc Bloodmage of Taurog is an insane melee fighter, not less than any Berserker or Rogue, thanks to plenty healing.)
I just killed all the monsters here, usually it takes 5-10 kills to win a dungeon.
But Mana Burn became a problem now, I didn't unlock Soul Orb yet, just too lazy... But WEYTWUT+Codex and if you a lucky + Orb of Zot truly makes wonders. I did Hoarder in Naga City With Codex Wizard.