I'm ashamed to say, in all my years of DIYing, I had never mastered the sliding knot. After the, like, fifth tutorial (tonight), I found this method. The secret is using a second (separate from the jewelry piece) cord for your loops and knotting. This method leaves 4 "tails" (2 from the ends of your piece, 2 from the 2nd cord). It worked the first time (on leather, even!). Give it a shot if you've struggled with knots in bracelets or necklaces, or just need a quick, adjustable closure!