Gather a small core object, such as a marble, bead, or tightly crumpled piece of paper
Choose elastic bands of similar size to begin with
Wrap the first band tightly around the core
Add a second band crossing over the first at a different angle
Keep wrapping bands around the center, alternating directions
Make sure each new band is snug before adding the next
Continue building evenly to form a stable base
Use smaller bands first if available
Add larger bands as the ball grows
Rotate the ball often while wrapping to keep the shape round