Do dailies for the stamp collection 1k. Play TOP using Regen or Son Fam and make sure you never use the heal or team change tiles to max your score. Even if you hate PVP, just until you win once every day for the daily win bonus (should get you 300cc every reset). Play the events and prioritise those that give more cc. Do adventures to get all the cc missions. Play story and clear all the challenges. Use the daily let's fight to get characters to friendship 5 and move to the next character.

Can't stress this enough, have the patience to skip banners. I only summon during Anni and Festival. It's usually easy to have 60-90k saved for these events just by doing this.