As a tank, what should I know/do to make it easier on Healer?

[Amelia_Pond_Behemoth]

Best would be to play as healer as well to get perspective insight.
Experience is best.

I can't agree with this statement enough. I'm no pro healer. I play WAR. However, since your main seems to be PLD, it wouldn't be a bad idea to pick up Stoneskin on CNJ. Use that time to learn from a healer's perspective.