When you take a look into the mage skill tab, you notice that you will only have 4 attack spells, which basically conclude your mage skills. The rest are mostly support or passive which you had to decide yourself. You can also mix with some priest tab skills such as summoning if you like extra companions. There are various ways to build a mage, be it pure or hybrid, but most important I think is build something which suit your play style.
Here a link to and old thread on mage guide where you can use as reference if you like to
The official "ULTIMATE MAGE" guide 
