From Aura Kingdom Wiki
As the Wizard have a natural boost to critical damage, it is recommendable to go offensively for critical chance as it is proven to affect overall damage better than investing in DMG stats (only true if you have high critical damage, if going for this, you need a lot of boost there). A bit of speed isn't bad at all, especially if going for secondary classes like sorcerer or bard that need more cooldown, but it may be personal preference until that point.
Mostly HP or defense (I went personally for defense). you don't get that much evade potential as other classes and HP may be more useful as a lot of equipment gives percentage boost.