Here are some more tips I picked up through experimenting:perspective, massing models, angles, lines and over the shoulder shots.
Lines are also visually pleasing:horizontal or vertical.
Also try to photograph over the model's shoulder so that you feel as if you're in their shoes. This makes the photos dramatic and personal.
You can create a menacing atmosphere if you photograph from the villian's point of view.
Hope these tips spice up your wargame photos and allow you to appreciate your models as well as scenery!