Overly broad shoulders are difficult to deal with, especially when they are paired with a very small or very large bust line. You can learn to accentuate the positive and play down the negative, though. Just a little style advice will do the trick.
Step 1 Wear close-cut necklines rather than square or boat neck styles. Necks that are scooped are fine if they have a narrow scoop, and high v-necks that draw the eye away from the shoulder area but don't plunge and accent the bust are also good.
Step 2 Choose jackets that have no details or color changes at the shoulders or upper sleeves. Look for very narrow lapels and avoid shoulder pads or pleats.
Step 3 Look for blouse or blousy sweaters and dolman sleeves that are wide at the top and narrower at the bottom--sometimes called bat sleeves. Necklines should be more vertical than horizontal.
Step 4 Longer garments with simple lines work better as do loose fitting soft form styles that drape the body with lightweight fabrics. Avoid boxy styles and anything that fits tightly across the bust line or shoulders.
Step 5 Select wrap front dresses and blouses that aren't made out of overly clingy fabrics. Avoid puffed sleeves, gathers, detail work such as beading and glitter, ruffles and shirring around the neck or shoulder area. Wide belts are not a good match either and avoid empire waistlines which draw the attention to the bust and shoulders.
Step 6 Looking great is only a matter of knowing what works best on your body type. A few simple fashion tips will have you looking like you already have the body you always wanted.
From: How to Dress to Hide Broad Shoulders | eHow.com link