This is the classic Mage PvE build. The one skip linked is a little bit more advanced.

Skills: 4/5 fire (no scorch), 4/5 light (no shock), 4/5 ice (no shatter), 4/5 shield (no wave), 4/5 clock (no time bomb)

Passives: 5/5 crit, agility, knowledge, might

Skill Swaps: Use fire, ice, shield, clock on mobs. Swap clock for light at boss.