True Casting is good for nuking multiple opponents with SR (say, cast True Casting and then Cacophonic Burst).
Assay Spell Resistance is good for continually attacking one opponent with high SR.
Regarding conbination of actions, there can be a lot of options if you learn spells such as Arcane Spellsurge, Arcane Fusion & Greater Arcane Fusion.
Other than that, actually increasing your caster level is always good, not just for penetrating SR. Ioun Stone, Ring of Arcane Might, Heritage Feat, various class features and such.