Try not to die. Help tips has some advice. To take the really really simplistic approach, a warrior can't attack you if they can't get in the same room with you. Keep alert and run like hell if someone you know wants to kill you is coming for you.

The more complicated and variant strategies depend a bit on who you are. Obviously you're a mage, but each of the mage classes are going to have to go at that in different ways.

Don't get too hung up on levels; they don't mean very much in PK. If someone's in your PK range, you've got a shot at beating them.