I just hit 15 on my arcanist yesterday and today I will be a White mage. Now, my question is the proper way to play one?

Usually they way I do it, I stand in the back and wait for everything to aggro the tank and I heal. Depending on the situation, I wait till about 40-50% health loss before healing, cause spamming it its honestly a waste. I've been reading about stance-dancing, but I never had the use of it unless I solo. Reason? Because the other roles know how to play accordingly so its never been an issue

I just wanna make sure Im playing my role correctly, and if not I wish to learn how to.