New tank here, have some random questions.

[Kabooa]

Second, how do you recognize tank busters? Is there some kind of specific tell or do I need to just pop sheltron every time it looks the boss is winding up for something?

Early on, 'tank busters' are just instant cast attacks that deal higher damage. You don't really get into the standard tankbuster design until 50+.

However, in almost every fight, the "Busters" happen first, of raid and tank variety. I can't say if it's one or the other every time, but generally, the first two ability names that pop up will be tank or party buster for the last boss of a dungeon.

In 90%+ of cases, those 'busters' are also cast time abilities with a few exceptions, such as the Yol in Bardram's mettle, who don't care none bout fight conventions.