Shorts aren't just a summer thing anymore...especially for petites. In Seventeen's September 2010 issue (now on newsstands), the article "Make Your Body Look Amazing!" explains that the best fall piece for petites is fall shorts.
What exactly are fall shorts? Pretty much any dark, solid-colored shorts that don't scream summer (steer clear of neon shades, big floral prints and the like). They can be cotton, wool, modal but stay away from linen shorts, which are more summery. They can be boy short length (just above mid-thigh) or shorter but make sure they look polished.
Try A&F's Kaylin shorts ($38)--the muted colors look very chic for autumn, and the pleats will help fill out your small frame.
Hollister's Bay Shore twill shorts ($15.89) have a classic look that's great for summer and fall. Plus, it's shorter and slimmer fit will make your legs look super long.
For a great denim option, go for American Eagle's AE Boy Fit Dark Denim Shorts ($39.50). The dark wash makes them nice enough for dinner out, but the destroyed style makes them casual, too.
When the weather cools down even more, switch up your style by pairing twill or wool shorts with tights to keep you warm and looking great!