One other trick that someone gave me once when I was wandering all over the stage was to put on the ground something (maybe a dry erase marker) that I could put a foot on. For some reason, that really helps to keep you in one place and you don't even really notice the object while you are presenting.
It's OK to walk, it releases nervous energy. Use a short walk to introduce a pause in your talk. Only speak when you are looking at someone and you will speak conversationally.
