As I begin to work my way through Piecing the Piece O'Cake Way the first skill I have encountered is rotary cutting -- specifically cutting strips. Now I've done rotary cutting before and it seems that everyone has their own way to go about doing it, but I think that focusing only on the way in the book was good for me. Before this I had my own method which was confused by the quilting teacher that I took a class from about 1 1/2 years ago -- leaving my method a mixed up, sloppy mess. So I think it was good for me to really focus on this one simple skill without distraction.
Next skill -- accurate 1/4" seam allowances.