If you fall into the rectangle category your in luck! Women with a rectangular body type already have a balanced body silhouette. Broad shoulders, and equally broad hips. The only thing you are missing is well defined waistline, but don't worry, that's an easy fix!
If you have a rectangular shaped figure your probably running a little low on curves. When choosing outfits you want to avoid anything that would accentuate this "flaw". Stay away from boxy cut jackets, tops without contouring, or anything else that would add bulk to your mid section.
There are two ways to approach the task of flattering a rectangular shaped figure; a. you can try to cinch in your waist by adding a belt, sash, or corset; or b. you can play up the volume of your hips and shoulders which will in turn give the illusion of a smaller waistline in contrast. To get the most bang for your buck look for pieces that can do both - such as wrap tops and dresses.
When shopping you want to look for pieces that add more femininity (aka. Curves) to your static shape. Think girlie tops with puffed shoulders, or jackets with detailing that visually widen your shoulder span; military styles with epaulets, or extra detailing such as ruffles. On the bottom try skirts that flare away from the body, or dresses that fit closest at the empire waist before flaring out.
Another way to draw attention away from the mid section and give the illusion of a curvier shape is to wear tops with deeply V'd necklines, and add a splash of color in a cami underneath. Doing so will draw the attention up and away from your waist. Also, try pairing casual tops, and princess seamed blazers with "skinny" cut jeans or pants that tapper towards the ankles. A skinny cut leg will make your hips look wider and maximize the contrast of your waistline.
Need a quick fix for a wardrobe that doesn't quite follow these rules? Buy a belt, or two and wear them over everything - is the cheapest and quickest way to get your wardrobe back on track!