White Mage is by far the easiest, I would suggest you go Astro its much more engaging and about the same difficulty as Whm.

1. *Mind is your main stat.* The other stats you want to look for is Vit, piety, crit, Det, Sps, and Dh.

2. Your main priority is to keep your party alive while also helping out in other ways like throwing out Dps. Basically follow "ABC" always be casting abilities.

3. Be proactive when playing a Healer if you know the fight.