Amy Herzog has an absolutely fabulous series on her blog called Fit to Flatter. I've been reading through it in dribs and drabs over the past week or so, and I have learned so much. Heck, even if you're not a knitter, the first few chapters are worth a read - it takes the basic 'apple / pear / hourglass' formula and adds extra nuance to it.
The series helps you to a) identify your body type, b) figure out what kind of clothes flatter that type, and c) choose patterns or adjust patterns to suit your body. The beginning lessons are more general, and toward the end she gets in to specifics on how to alter a pattern to suit your figure.
Maybe it's old news to some people, since the series is a couple years old, but the advice is timeless and well worth a look. For instance, I learned as a bottom-heavy shape, colorwork yoke sweaters would flatter me because it draws the eye upward, balancing out my wide hips and my narrow shoulders. And I already knew that it was more flattering to wear a dark bottom and a light top than vice versa, but now I know why - for the same reason, attracting the eye up to my top half.
The series is available free as a series of blog posts, or you can buy it in a nicely formatted, go-anywhere PDF set.