I am not a baker and I certainly am not a food stylist but I did find a super easy and fast way to create a cake banner - out of desperation of course. I waited till the last minute to bake and decorate a cake for a party and then scrambled to find something to make it "cute" (by my standards).
Using twine and post-it flags from the dollar section at Target I constructed a banner in literally 5 minutes.
I wrote my message on the flags first and then folded the flag in half over the twine using the natural sticky back to keep it in place. I then tied the twine banner to two wood skewers (or straws) to finish it.
And it looks cuter in person - cell phone pictures don't do it justice.