>>718411707
I open big fights with a frost proc; there's a handful of options including DMGS. I like zamor ice storm and dark moon.
Glintblade sorceries like phalanx are really good for keeping up stance pressure on bosses. They let you use a smaller/faster weapon and still stance break, ideally the carian sorcery sword, which is very fun to use with a medium shield or even the main-gauche. If the boss is wasting time with a big AOE or floating in the air, you can set up a whole mess of projectiles that it won't dodge.
Large enemies like dragons and furnace golems get chewed up by the spiral spell at the end of Sellen's quest, and you can delete entire groups with cannon of haima, very satisfying.