One of my favorite trends that carried over into fall is the midi skirt, mostly because I have a closet of them that I haven't worn for years! A way to modernize what you have tucked away in storage is to add a cropped top. Not the belly-baring cropped top that you might find at Coachella (although clearly there is a time and place for this), but something on the more structured, edgy, yet conservative side.
Although I don't believe fashion should have rules, I do believe that sometimes it's good to keep things classy by abiding by a couple "rules of thumb":
1. To make a cropped top and midi "work appropriate", it's critical to not show skin. How to avoid? Wear a high waist skirt so the shirt overlaps just enough. Zara does it best in their fall collection - check it out here.
2. Stick to a simple pallet for both the midi and the cropped top. Stripes and solids. Neutral colors. Red is definitely OK too!
3. Midis can be a funky length, so be sure to elongate your legs by wearing a fun bootie, shootie, or pointed toe pump.
4. Compliment your midi/crop outfit with big pieces of jewelry that have understated design elements.