What is the proper way to "break" a boss? I'm always doing it wrong, is there a trick?
If you are referring to how to get the "Breaker" 1st rank within the party,I'm not too sure myself.There was one time I simply used Archer and shot multiple skills of ailments,then attained the 1st "Breaker" rank all of a sudden.
If you are referring to how to specifically break a bosses' part faster,there is no trick.Tap damage vary depending on your character level so which means the higher your character level is,the faster you break the boss.Do remember to actually get the chance of breaking the bosses' part,you need to inflict either Tumble,Flinch or Stun status.
Flinch : Can be inflicted various of times,inflicted by tons of skills and bosses have the lowest resistance to it but it also possesses the lowest Tap chance time.
Tumble : Can be inflicted various of times by specific skills,have moderate Tap chance time and the bosses have the same resistance to it as Flinch.
Stun : Can be re-inflicted once certain times have passed after the first inflicted stun,restricts the bosses' movements and action while also possessing the highest Tap chance time.Bosses does not posses resistance toward this status,however it requires certain time until it can be inflicted again.
Extra Notes : To effectively break a boss's part,learn the spots of its Tap chances before engaging.That may help reduce the time for you to find the spots themselves rather than focusing to breaking themselves.You may also bring a good breaker to do the job while you do damage.
Remember Breakers require time to break all part,or you can contribute to help them.So don't just one-shot the boss while the breakers make an unhappy face.