First you need these supplies:
1. Any type of string
2. Beads you want (Letter beads, color beads, wood beads, etc) to use in your design
3. Key ring
Cut the string to however length you want it to be, then cut the string.
After you cut the string, fold the string in half, put both of the string ends through the ring.
Pull the cording until the middle of the string is near the ring
Next, put the ends of the cording through the loop, pull through and tighten it.
Thread both ends of the cording through beads. Be sure that the beads you chose have holes that are big enough for two strands of cording. There are a large variety of pony beads, alphabet beads, number beads, and plastic beads that work very well.
Tie a double knot at the end to secure the beads. Then you can trim the extra string off.
Enjoy your keychain!