I used to make a lot of clothes. Two memorable mistakes boil down to the same thing: putting sleeves in backwards twice, and in junior high sewing class, attaching the top of an apron backwards to the bottom, several times with the help of my sewing teacher. She gave me a generous C in class, and knew I'd never amount to much. I had a hard time learning to use a thimble, too. The end of that story is that I did learn, and ended up writing for Threads, Belle Armoire, etc. I showed her!!!