Form an open-ended loop in the fly line (or larger diameter monofilament). Pass the backing (or smaller diameter strand) through the loop and take one turn around fly line.
Wind the end of the backing around itself and the fly line loop. Take 10-12 winds, keeping them in place with left hand. Pass the backing through the loop so that it comes out on the same side it entered on.
Slide the coils of backing together and toward the end of the loop, stopping 1/8″ from end. Take care that backing does not slide off end of fly line before tightening.
Tighten by pulling on the tag end of the backing while holding both strands of fly line in left hand. Pliers or a hemostat can be used on tag end. With left hand still holding both ends of fly line, pull on standing part of backing. Pull tag end of backing again and standing part one more time. Complete tightening by pulling only on standing parts of fly line and backing.
Trim the tag end of fly line and backing.
Note: The thin monofilament should be doubled when attaching thin monofilament tippet to heavy monofilament shock tippet.