All your plays should revolve around shield management. You NEVER want to have a broken shield, even if it means dropping the shield at 100 and never bringing it up again until it recharges. This is because as long as you still have a shield, you can still block pulse bombs, self destructs, one widow headshot, you get the idea.
Call our shield health at different intervals, also call out when you need to drop shield. If you don't have mic then ignore this point.
Only Shatter when you know that you can get the kills from it. A full team shatter is a waste if you don't get any kills.
Don't ever charge into a choke on the attack unless your team is playing dive or you have a support ult to back your charge up. If you blind charge into a choke defense, you will die.