As a level 6 mage, you don't have but a couple of spells... Use your mouse to move, your keyboard to straffe and hotkey your main weapon to '1'. Make sure you're using the highest rank spell as well.
Shouldn't be too much to it. You should not be doing PvP at that young age, so I'm assuming you mean mobs are killing you.
Remember that max range is your friend. Nuke away.