When it comes to layering your midi dress, it all depends on the dress itself. If your dress has a graphic print or is made of a fun fabrication (like sequins), you want to let the dress be the star of the show; the layers surrounding it should be understated, whether that's a coat, or jacket, or scarf. But if your midi dress is quite simple, you can layer it with an eyecatching blazer, a leather biker jacket, a fuzzy cardigan, or even sneakers.