Shield resists come from material only, currently, for craftable shields. Each shield comes with only 1 resist per shield, (varying by shield type). Choosing the proper ingot type can add 6-13 more, in the normal spread for that material (see the charts on the main stratics page, uo.com or other sources as to the metal types).
The rest you should be able to do with a copper or bronze runic, as there are so few properties than can be on a shield (those 3, Lower requirements, Durability, Self Repair, and Reflect Physical)