Help!

I'm currently trying to make a poster describing my thesis (which is on mediaeval literature, more precisely on Mechthild of Magdeburg). And I'm finding this really tricky: I'm using Powerpoint, and I'm going to print it at A3, but I'm worried about it ending up overloaded with text.

Has anyone out there had to do this sort of thing, and do you have any tips?

ETA: Google Images does produce some strange links. I expected the esoteric stuff, but I can't imagine why "Das fließende Licht der Gottheit" produces a German page on imagery in Terry Prachett...