After completing the weaving I carefully lifted the knot off the board and began tightening it up by pulling on the paired strings from the bottom.



This is really tedious, and takes more time than the actual weaving. Be patient and think nice, calm thoughts. Be sure that the paired cords remain flat and don't cross over one another.
Here it is nearing completion. Keep pulling until all the slack has been eliminated and you have the two loose ends hanging off the bottom of the knot. Trim them down and melt the ends with a match, quickly mashing them into the braid on the underside so that they will stick there out of sight.



Here are the two completed knots.



And here is one attached to the jacket. A few stitches with stout black thread holds the end at the point of the shoulder, and an appropriate button stitched through from the underside holds the other end.