Let it be known that I'm totally jealous of you teachers (or whoever) that gets to participate in real Casual Fridays. It's not really a thing at my office, but my sister gets to celebrate every Friday...with jeans! Here's a few ways to dress up the denim for the casual days:
Add a pop of color to an otherwise neutral/blue getup with a bright contrasting cardigan. With or without front buttons, cardigans always seem to make me feel comfy, cozy and more relaxed.
If you're a fashionista that enjoys an occasional jean day, stay "dressed up" by adding a floral top. You'd probably normally wear this type of top with your dress pants, but pairing it with jeans is just as flattering!
Glam up a super casual outfit with the glitz of glittery TOMS. We love the classic pink ones, but now they offer a sequined pair which may be even better!