Simply use the basic knot you’d use to make friendship bracelets to wrap the main cord and each of the individual earbud cords. To make them even more tangle-proof, wrap plastic coated twist ties inside with the cord.
Joining panels or strips as you go. Crocheted blanket tutorial showing how to join squares while crocheting (instead of just stitching together at the end). Results in a beautiful eyelet row between strips.