Been maybe quite some time since I played my character Dialya, but I am trying to return to the game, but forgotten how to mage? I was a Nexus Magus with a summoning companion, but with so many spells at lvl 63, I am clueless. I quit prior because I could not beat that dragon for the Power of Greed quest.

Is there a better spec that will help me burn mobs down? I don't own the game by using real life currency/or don't have gems. So like pay to get a spec unlocked is out of the question.