fists of fire for damage obviously. sometimes if the fight or phase of a fight requires it i'll switch to earth/wind for a short amount of time until w/e it was is over and then switch back to fire. just need to get used to stance swapping depending on the situation.

Trash mobs I'll spread DoTs or maybe even use rockbreaker if 3+ enemies to not apply too much aggro on one thing to help the tank, and also to increase my overall dps to make the dungeon go faster.

normal rotation on a boss:
DK>twin>snap/demo

at the very start however ill do a bootshine from behind instead of DK because DK doesn't apply the debuff for the first rotation since you're neutral and no opo-opo yet.
keep demo, fracture, touch of death, twin snakes, dragon kick, GL3 up. since dots dont require positioning i dont worry about the position for those. 95% of the time i'm at the flank, the only abilities requiring being behind is bootshine, and true strike. you won't be using those cause youll be too busy reapplying DK and twin snakes instead which are from the flank, and snap punch is the flank. only time i go behind is for a bootshine at the start or a bootshine when restarting the rotation after my stances dropped due to a boss mechanic.

remember to shoulder tackle when you need it.
remember to steel peak when it can be helpful.
remember mantra has a small radius, i normally use it when people are close together and i know we'll be taking a bit of damage soon, like when garuda HM summons the sisters.
remember to use second wind, foresight, the dodge ability i forget the name when you might be taking a bit of damage to make it easier on the healers and for the group.