It doesn't sound like you are making mistakes, it sounds like your "artistic vision" is not achieved in the real quilt. This is my life. I can picture it in my head, I draw & color, I drop in fabrics in EQ7. Then I actually piece it and yech! Normally I think I've just been looking at it too long. I don't rip, I just put it away for a few days. Usually looks better after a rest (both me and the quilt).