I hate two piece matching sets. But I adore the combination of varying shades of the same color. It's the modern version of the matching outfit and I'm completely here for it.
Although I just wrote an article on kimonos, I felt compelled to include them on this list. To me, kimono's are ideal outerwear for summer. Sometimes when you're wearing a tiny cotton dress, you want a little something extra to enhance the outfit. Look no further than the kimono.
My other trick for layering during the warmer months is to leverage my button down shirts. Since they're lighter weight, they bring a bit more sophistication to your outfit without adding bulk. On the top of my wish list is a button down camo shirt. It's been a little tricky to find one, so the strategy now is to find a man's camo shirt in a small size. Another great layering option is a chambray shirt. Pretty much any button down can serve as summer outer wear so have fun experimenting.