As a lowbie invoker, you need to gear for hp and only that for every single item slot. Your goal is to cause as much damage as possible before they can kill you. Also, find a source of money or lightweight barterable objects so that you can pay to heal yourself.

At the start limit yourself to attacking things that are 1) vulnerable to an element you know well (cast wall of fire on felars, etc), 2) have low hp (any mage) and 3) cannot lag you (warriors pre-15).

Remember, you are ALL offense.