I've been asked many times how I finish my flat ornaments, like the clef series. I do use this finish a lot because of how simply it goes together and how nice it usually comes out. I do use glue and double-stick tape, so some of you purists may be put off by this cheating and I give you this chance to avert your eyes.
Gather up your materials and tools. Press your stitched piece. I use acid-free mat board (the blue rectangle), wool felt, Warm & Natural quilt batting, and beads.
Now for the glue. I use "Fabri-tac" by Beacon Adhesives. This stuff is stinky (not for people with VOC sensitivity) and super sticky. Try very hard to not get any in places you don't want it. One corner at a time, put a blob inside each miter area and under the wings, then squash it down flat and hold it in place until it stays there. Double-check which side is the top then add a loop of trim for hanging, using the glue to cement it in place. Draw a line of goo in a box about 3/8" inside of the outer edge.
I hope you find this technique helpful. You can also use a twisted cord or some other trim instead of the beads. Try it, then show me your finishes using it.