- let them fray - this is great when you're going for more of a casual, bohemenian sort of look
- fray check, available at fabric and craft stores
- my favorite method: run the cut end of the ribbon quickly through a flame. Do this in a well-ventilated area!!! I'm serious! This only works on man-made materials that melt in heat, so it won't work for natural fibers such as cotton or linen.
If you trim your ribbons, they will most likely fray without using some method to seal the ends. Here are my favorite things to do with the ribbon ends: