I reached for a couple of items that automatically glitz up any project; Disco Dust, and 4mm sugar pearls (which are especially appropriate, because the ladies in the show all have pearl necklaces on in the publicity shot; the cupcake papers approximate the colors of their dresses, as does the frosting).
Disco Dust is unbelievably easy to apply; I'm assuming it has something to do with static electricity. All you need to do is touch your finger to it, then touch whatever surface you want to apply it to. I'm sure you could get more precise by using a brush, but it tends to go everywhere, no matter what. Here are the music notes after being dusted:
And here they are awaiting demolishment at the gala.
Here's a shot of those aforementioned Wonderettes…you can see how they inspired the cupcakes, right?