Step 1: Get your favorite double sided adhesive paper. This is what I happened to have on hand.
Step 2: Peel the backing off your adhesive sheet and adhere to a 5 1/2" x 4 1/4" card base (I used white, but any color will work). Trim off the excess.
Step 3: Choose the glitter colors you'd like to use. You can do as many or as little colors. I decided on two.
Step 4: Peel off the top protector on the adhesive sheet
Step 6: Finish by adding the second color and "flicking" off the excess after each pour.
Here is the finished sheet. Now it's ready to finish decorating.
And here is the finished card using this background