I learned how to transition my skirts, dresses, and even shorts into fall and winter. The answer is so obvious, but I couldn't grasp the concept until my junior year of high school. LEGWEAR!
From tights (footless and footed) to socks (ankle, knee-high, over-the-knee, and thigh-highs there's absolutely no reason that you can't rock your favorite pair of shorts or a skirt in the fall or even winter for that matter! Tights and socks come in so many different kinds of fabrics, styles, and colors that it's impossible to not find one that will absolutely transform your wardrobe!
So don't be scared to make that "summer" dress work for the fall. Fashion is not fire, you can play with it and still have fun! :p
But most importantly.....
Make . It. Work.