I based my shield a bit on one that was given. I wanted it to have a wooden look of dark and light. The runes and colors I wanted to give off a magic variety but to have a somewhat tribal look by the red hand print at the bottom and symbol and horn like symbol on the sides. The red and brown are suppose to be repetitive and theirs colors are meant to look worn and aged as well as the small details like the cracks in random places and darken blood like smears in other sections. Overall I wanted the shield to look like it had been through a rough journey but is sturdy looking enough to take on many more.
This was my reference:
iadtgame225_Texturing and Lighting 