General Tips
P1-P2: Save Mudra if it comes back up while he's splashingx3 before the transition. Cast Suiton as he finishes transforming and TA right before or after cleave (will be up before hand of pain check).
Only stand in front for the cleave, hit rears/flanks otherwise.

P3:
You can hit the tornado to queue up your 2nd combo and run out of the puddle without getting damaged. Pop all CDs once early here including Sneak/Trick Attack for the Piston in the 3rd wave: save Jugulate for Piston stun, especially last wave.
You can also Katon the tornado right as a wave spawns and hit everything except the tornado itself for some damage.

For reference, I end at around 1200 dps as P3 starts at iLevel 200