I do the tutorial with fat yarn and a size N crochet hook for better visability. It is also a very good idea for beginners to start out with thicker yarn and a larger hook so they can practice before going down to the skinnier threads and crochet hooks.
The hackey sack can be made using the pattern I will provide here, 1 or more balls of #3 crochet thread, and a size 2 crochet hook.
Step 1: Make the slip knot.
Gently tighten the noose around the hook (pic 5).