Obviously the first step is to try a bit of lubricant like Windex, but this method—while a bit complicated—should work really well. It's very simple and should make it much easier to understand the process. Essentially, you wrap the elastic band tightly around the finger, moving toward the ring as you go. Once you get to the ring, try to feed the band through the ring. Once you do, you should be able to start unwrapping the elastic and it'll bring the ring with it.