>>714357403Stock up on Starlight Shards.
The main thing that'll kill a run is whether or not you're comfortable with the cast time of a spell. Pebble, Slicer, Catch Flame, and Bestial Sling are your R1s, everything else is an R2 or slower. The best ones are all slower so ideally you get used to it.
Turn off autotarget in settings. Webm rel, it's on by default and makes some spells unusable at a distance.
Rally relic puts in a ton of work with multihit spells. Getting hit while spamming Magic Downpour or Rancorcall will have most of the damage healed by the time you stand back up.
If you find Burn O Flame, you win. Even as Duchess. Even against fire resistant bosses. The damage is unreal.