I made one a while back out of boredom. You can use this to make necklaces as well.

Supplies

WHAT YOU NEED

Two shoelaces
something sort of jewelry clasp or buckle(optional)
a lighter(optional)

Step 1: Starting the Lanyard(For Clasps and Buckles)

Take your shoelace and loop it through the hole in the clasp/buckle. Pull until both both halves of the lace are the same length. finish with a knot.

Step 2: Starting the Lanyard(alternate Buckles)

Take your shoelace and loop it through two buckles. Pull until both halves of the shoelace are equal. Finish with a knot.

Step 3: Starting the Lanyard(no Clasps or Buckles)

Make a loop with one of the laces. Thread the other shoelace through the loop. Finish with a knot.

Step 4: Making the Lanyard

Now with the starting knot in place, you can begin. Start by making another knot, repeating until you reach the end. DO THIS FOR BOTH SHOELACES.

Step 5: Finishing the Lanyard

If you're using a lighter, melt the plastic tips together in a fashion similar to paracord. If you're not using a lighter, undo atleast the last two knots on both laces and tie them together, connecting the two halves. That's it! your lanyard is complete!