Choose your prettiest buttons. Starting with the center, work around in a circle adding different colors and styles. The pearl tone buttons are pretty, especially if they have delicate colors of pinks, blues, yellows. Use a glue gun to hold this firm. The cool glue gun doesn't stick as well but in combination with white glue, the pin back will be solid on the back.
Buttons come in all different shapes and sizes.
The designs for children offer the most variety. There are cats, dogs, icecream cones, faces, elves, and other characters in children's buttons. Mixing colors also adds to the attraction of a button jewelry pin, though a monochrome is also interesting. Don't worry if the buttons extend beyond your cardboard circle. This is OK and lends to the design.