I made this last year for my son's Halloween costume. Gallery here... Link Costume
Step 1: Getting Started
I found a black and white version of the shield online. Printed it off and cut out the shapes from the paper. Then we just drew out each shape on the correct color foam and cut them out.
Step 2: Putting It Together.
I cut out a piece of masonite and blue foam in the shape of the shield and glued them together. Then I laid everything out to make sure it looked right and started gluing on 1 piece at a time.
Step 3: Finishing It Up
I wanted it to double as a safety device so I went to the store and got some reflective tape. Reflective tape can be found at auto parts stores, walmart, and home depot.
Now that it is finished and nice and shiny I glued it on to the shoulder strap on the costume.
Step 4: The Possibilities Are Endless.
I also made this family crest using the same technique. It was for a school project for one of the boys but I kind of took it over. It is completely made up. You can use this same process to make any kind of shield you want.