Mostly you need to practice more and panic less xD

When you are more used to the fight and get voice, you can try and force/save a proc (or SC Flare - Transpose) to cast on 1/2s remaining, then turn for voice while the GDC is being refreshed.

As soon as you get Shriek, unload everything you can while running into position and transpose to get back to full mana.

Keep Thunder on boss even when adds are up for possible TC procs.