Place some bird seed in the middle of a 6 inch square of cloth. The color of the cloth relates to the type of magic the packet will be used for (see the section on Magic for more details on colors, near the end of part 1). Draw up the corners so that all the bird seed is contained in the packet with none leaking out, and fasten the corners closed with a rubber band. Make sure the packet isn’t so hard that it will hurt when thrown; the birdseed should still be somewhat mobile within the cloth. A tutorial can be found here.