Last year, I took a class on fitting and pattern alteration. At first, I wasn't too excited about taking it because 1. It was in the summertime, 2. My kids are out of school in the summertime and 3. It was in the summertime! Nah, it was mostly because I thought I already knew how to alter patterns. As the class progressed, I quickly realized I didn't know it all and that there is always more to learn. In class we talked about figure types, lines, shapes, pattern making, grading, husbands/boyfriends and of course how to alter patterns.
In the end, it was a class I loved and enjoyed so much that I ended up doing way more alterations than I was required to do. It was fun!
Anyway, just thought you sewists out there would be interested in this fitting and pattern alteration book we used (and I still use). It's extremely helpful to have in your sewing library, especially when making clothes for other people. There are 80 plus alterations in this book with clear and easy to follow diagrams on how to alter bodices, sleeves, skirts and pants. The good thing is, I've tested all of them and I know for sure they work. Pretty darn awesome!