I made two shields a few weeks ago. They were my first leather work of any kind as well.
First one, I carved, dyed black, painted with acrylic, and topped with 50/50 Resolene/Water. Not sure how well that one's going to hold up. Second one I did like rawhide described. Letters cut from leather & epoxied on, everything else saddle stitched by hand with waxed thread and two needles. Wore this one in a training fire last weekend. It held up pretty well through almost certainly the worst conditions it'll ever see.
Got almost everything from Springfield leather. I highly recommend them, they're great. I got 2 lbs tooling leather remnants which came with a bunch of really nice leather, in perfect sizes for things like shields. Hard to beat for $4/lb.