Tank playbook

Setup & first fight

Play at the front and claim space near cover: the ground you hold is where your team gets to stand and shoot.
Your movement is the team's call. Walking forward starts the fight and backing off signals a reset, so make both obvious and say when you're going in.
Hard-commit only when your supports can see you and your damage players are in place to follow. Otherwise show yourself at the corner and hold.

Spend barriers, armor and movement on purpose. Pressure the enemy into using their defensive tools, then push while those are down.
Keep an eye on your backline. When a flanker dives your supports, turning to help them often matters more than the tank duel.

Don't use your ultimate to finish a fight you're already winning, or when your team is too far away to follow it up.
Know which enemy ult or save can cancel yours (a Sound Barrier, a Suzu) and get it used before you commit.
Track a few enemy ultimates rather than all five: the one that wins fights and the one that saves them. Judge their charge from last fight's damage and healing and from how long ago they used it.
Avoid stacking two ultimates to win one fight, especially into a counter you haven't baited. It leaves you behind for the next fight.
After a lost fight, stop taking extra peeks. Back off, meet at one spot and go back in together, because trickling in one at a time loses the next fight too.

In a must-win fight, a tank ult is worth using to take back space or the objective even if it doesn't get kills.
Overtime only holds while someone alive is actually on the objective (point, payload or robot). Standing near it doesn't count.
In a round's final fight there is nothing left to save ultimates for, so use them freely.