Some of the trouble was mastering the technique, and I did improve with practice.
But I quickly realized that some of the trouble was the thread. I was using linen embroidery thread, which tends to splinter and separate easily. On a new ACEO, I used vintage cotton thread with results that made me quite happy.
Though it IS difficult to photograph something so tiny . . . you’ll be seeing more of this ACEO when I post it in my Etsy shop. But I’m keeping the one with the wonky knots.