On the days that I have "nothing to wear," I often turn to the most basic outfits. It's always a kind of duh moment when I realize a crisp white blouse and dark jeans is the perfect outfit 9 out of 10 times. I dressed mine up a bit with a killer pair of heels...when all else fails, just add heels!
Also, just add adorable leather bow you picked up for $5 at the H&M checkout stand. Impulse buy, but I love this thing.